Method and apparatus for video coding

ABSTRACT

Aspects of the disclosure provide methods, apparatuses, and non-transitory computer-readable storage mediums for video encoding/decoding. An apparatus includes processing circuitry that decodes profile information for a plurality of image slices in prediction information of a coded video bitstream. The profile information includes profile identification information of a profile in which each of the image slices in the coded video bitstream is intra coded. The processing circuitry performs intra prediction on each of the image slices in the coded video bitstream. Further, the processing circuitry reconstructs at least one image picture based on the intra prediction.

INCORPORATION BY REFERENCE

This present application claims the benefit of priority to U.S.Provisional Application No. 63/007,187, “CONSTRAINT ON SYNTAX ELEMENTSFOR VARIOUS PROFILES,” filed on Apr. 8, 2020, and U.S. ProvisionalApplication No. 63/029,000, “GROUPS OF GENERAL CONSTRAINT FLAGS,” filedon May 22, 2020, which are incorporated by reference herein in theirentirety.

TECHNICAL FIELD

The present disclosure describes embodiments generally related to videocoding.

BACKGROUND

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent the work is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

Video coding and decoding can be performed using inter-pictureprediction with motion compensation. Uncompressed digital video caninclude a series of pictures, each picture having a spatial dimensionof, for example, 1920×1080 luminance samples and associated chrominancesamples. The series of pictures can have a fixed or variable picturerate (informally also known as frame rate) of, for example, 60 picturesper second or 60 Hz. Uncompressed video has significant bitraterequirements. For example, 1080p60 4:2:0 video at 8 bit per sample(1920×1080 luminance sample resolution at 60 Hz frame rate) requiresclose to 1.5 Gbit/s bandwidth. An hour of such video requires more than600 GBytes of storage space.

One purpose of video coding and decoding can be the reduction ofredundancy in the input video signal, through compression. Compressioncan help reduce the aforementioned bandwidth or storage spacerequirements, in some cases by two orders of magnitude or more. Bothlossless and lossy compression, as well as a combination thereof can beemployed. Lossless compression refers to techniques where an exact copyof the original signal can be reconstructed from the compressed originalsignal. When using lossy compression, the reconstructed signal may notbe identical to the original signal, but the distortion between originaland reconstructed signals is small enough to make the reconstructedsignal useful for the intended application. In the case of video, lossycompression is widely employed. The amount of distortion tolerateddepends on the application; for example, users of certain consumerstreaming applications may tolerate higher distortion than users oftelevision distribution applications. The compression ratio achievablecan reflect that: higher allowable/tolerable distortion can yield highercompression ratios.

A video encoder and decoder can utilize techniques from several broadcategories, including, for example, motion compensation, transform,quantization, and entropy coding.

Video codec technologies can include techniques known as intra coding.In intra coding, sample values are represented without reference tosamples or other data from previously reconstructed reference pictures.In some video codecs, the picture is spatially subdivided into blocks ofsamples. When all blocks of samples are coded in intra mode, thatpicture can be an intra picture. Intra pictures and their derivationssuch as independent decoder refresh pictures, can be used to reset thedecoder state and can, therefore, be used as the first picture in acoded video bitstream and a video session, or as a still image. Thesamples of an intra block can be exposed to a transform, and thetransform coefficients can be quantized before entropy coding. Intraprediction can be a technique that minimizes sample values in thepre-transform domain. In some cases, the smaller the DC value after atransform is, and the smaller the AC coefficients are, the fewer thebits that are required at a given quantization step size to representthe block after entropy coding.

Traditional intra coding such as known from, for example MPEG-2generation coding technologies, does not use intra prediction. However,some newer video compression technologies include techniques thatattempt, from, for example, surrounding sample data and/or metadataobtained during the encoding/decoding of spatially neighboring, andpreceding in decoding order, blocks of data. Such techniques arehenceforth called “intra prediction” techniques. Note that in at leastsome cases, intra prediction is only using reference data from thecurrent picture under reconstruction and not from reference pictures.

There can be many different forms of intra prediction. When more thanone of such techniques can be used in a given video coding technology,the technique in use can be coded in an intra prediction mode. Incertain cases, modes can have submodes and/or parameters, and those canbe coded individually or included in the mode codeword. Which codewordto use for a given mode/submode/parameter combination can have an impactin the coding efficiency gain through intra prediction, and so can theentropy coding technology used to translate the codewords into abitstream.

A certain mode of intra prediction was introduced with H.264, refined inH.265, and further refined in newer coding technologies such as jointexploration model (JEM), versatile video coding (VVC), and benchmark set(BMS). A predictor block can be formed using neighboring sample valuesbelonging to already available samples. Sample values of neighboringsamples are copied into the predictor block according to a direction. Areference to the direction in use can be coded in the bitstream or maybe predicted itself.

Referring to FIG. 1A, depicted in the lower right is a subset of ninepredictor directions known from H.265's 33 possible predictor directions(corresponding to the 33 angular modes of the 35 intra modes). The pointwhere the arrows converge (101) represents the sample being predicted.The arrows represent the direction from which the sample is beingpredicted. For example, arrow (102) indicates that sample (101) ispredicted from a sample or samples to the upper right, at a 45 degreeangle from the horizontal. Similarly, arrow (103) indicates that sample(101) is predicted from a sample or samples to the lower left of sample(101), in a 22.5 degree angle from the horizontal.

Still referring to FIG. 1A, on the top left there is depicted a squareblock (104) of 4×4 samples (indicated by a dashed, boldface line). Thesquare block (104) includes 16 samples, each labelled with an “S”, itsposition in the Y dimension (e.g., row index) and its position in the Xdimension (e.g., column index). For example, sample S21 is the secondsample in the Y dimension (from the top) and the first (from the left)sample in the X dimension. Similarly, sample S44 is the fourth sample inblock (104) in both the Y and X dimensions. As the block is 4×4 samplesin size, S44 is at the bottom right. Further shown are reference samplesthat follow a similar numbering scheme. A reference sample is labelledwith an R, its Y position (e.g., row index) and X position (columnindex) relative to block (104). In both H.264 and H.265, predictionsamples neighbor the block under reconstruction; therefore no negativevalues need to be used.

Intra picture prediction can work by copying reference sample valuesfrom the neighboring samples as appropriated by the signaled predictiondirection. For example, assume the coded video bitstream includessignaling that, for this block, indicates a prediction directionconsistent with arrow (102)—that is, samples are predicted from aprediction sample or samples to the upper right, at a 45 degree anglefrom the horizontal. In that case, samples S41, S32, S23, and S14 arepredicted from the same reference sample R05. Sample S44 is thenpredicted from reference sample R08.

In certain cases, the values of multiple reference samples may becombined, for example through interpolation, in order to calculate areference sample; especially when the directions are not evenlydivisible by 45 degrees.

The number of possible directions has increased as video codingtechnology has developed. In H.264 (year 2003), nine different directioncould be represented. That increased to 33 in H.265 (year 2013), andJEM/VVC/BMS, at the time of disclosure, can support up to 65 directions.Experiments have been conducted to identify the most likely directions,and certain techniques in the entropy coding are used to represent thoselikely directions in a small number of bits, accepting a certain penaltyfor less likely directions. Further, the directions themselves cansometimes be predicted from neighboring directions used in neighboring,already decoded, blocks.

FIG. 1B shows a schematic (105) that depicts 65 intra predictiondirections according to JEM to illustrate the increasing number ofprediction directions over time.

The mapping of intra prediction directions bits in the coded videobitstream that represent the direction can be different from videocoding technology to video coding technology; and can range, forexample, from simple direct mappings of prediction direction to intraprediction mode, to codewords, to complex adaptive schemes involvingmost probable modes, and similar techniques. In all cases, however,there can be certain directions that are statistically less likely tooccur in video content than certain other directions. As the goal ofvideo compression is the reduction of redundancy, those less likelydirections will, in a well working video coding technology, berepresented by a larger number of bits than more likely directions.

Motion compensation can be a lossy compression technique and can relateto techniques where a block of sample data from a previouslyreconstructed picture or part thereof (reference picture), after beingspatially shifted in a direction indicated by a motion vector (MVhenceforth), is used for the prediction of a newly reconstructed pictureor picture part. In some cases, the reference picture can be the same asthe picture currently under reconstruction. MVs can have two dimensionsX and Y, or three dimensions, the third being an indication of thereference picture in use (the latter, indirectly, can be a timedimension).

In some video compression techniques, an MV applicable to a certain areaof sample data can be predicted from other MVs, for example from thoserelated to another area of sample data spatially adjacent to the areaunder reconstruction, and preceding that MV in decoding order. Doing socan substantially reduce the amount of data required for coding the MV,thereby removing redundancy and increasing compression. MV predictioncan work effectively, for example, because when coding an input videosignal derived from a camera (known as natural video) there is astatistical likelihood that areas larger than the area to which a singleMV is applicable move in a similar direction and, therefore, can in somecases be predicted using a similar MV derived from MVs of a neighboringarea. That results in the MV found for a given area to be similar or thesame as the MV predicted from the surrounding MVs, and that in turn canbe represented, after entropy coding, in a smaller number of bits thanwhat would be used if coding the MV directly. In some cases, MVprediction can be an example of lossless compression of a signal(namely: the MVs) derived from the original signal (namely: the samplestream). In other cases, MV prediction itself can be lossy, for examplebecause of rounding errors when calculating a predictor from severalsurrounding MVs.

Various MV prediction mechanisms are described in H.265/HEVC (ITU-T Rec.H.265, “High Efficiency Video Coding”, December 2016). Out of the manyMV prediction mechanisms that H.265 offers, described herein is atechnique henceforth referred to as “spatial merge.”

Referring to FIG. 1C, a current block (111) can include samples thathave been found by the encoder during the motion search process to bepredictable from a previous block of the same size that has beenspatially shifted. Instead of coding that MV directly, the MV can bederived from metadata associated with one or more reference pictures,for example from the most recent (in decoding order) reference picture,using the MV associated with either one of five surrounding samples,denoted A0, A1, and B0, B1, B2 (112 through 116, respectively). InH.265, the MV prediction can use predictors from the same referencepicture that the neighboring block is using.

SUMMARY

Aspects of the disclosure provide apparatuses for videoencoding/decoding. An apparatus includes processing circuitry thatdecodes profile information for a plurality of image slices inprediction information of a coded video bitstream. The profileinformation includes profile identification information of a profile inwhich each of the image slices in the coded video bitstream is intracoded. The processing circuitry performs intra prediction on each of theimage slices in the coded video bitstream. The processing circuitryreconstructs at least one image picture based on the intra prediction.

In an embodiment, the profile information includes a first flagindicating whether each of the image slices in the coded video bitstreamis intra coded and a second flag indicating whether each of the imageslices in the coded video bitstream is included in one picture.

In an embodiment, the first flag is decoded after the second flag andindicates that each of the image slices in the coded video bitstream isintra coded based on the second flag indicating that each of the imageslices in the coded video bitstream is included in one picture.

In an embodiment, the first flag indicates that each of the image slicesin the coded video bitstream is intra coded based on the profileidentification information of the profile in which each of the imagesslice in the coded video bitstream is intra coded.

In an embodiment, the second flag indicates that each of the imageslices in the coded video bitstream is included in one picture based onthe profile being a still picture profile in which only one picture isincluded in the coded video bitstream.

In an embodiment, non-intra related syntax elements are not included inthe prediction information based on one of (i) the first flag indicatingthat each of the image slices in the coded video bitstream is intracoded and (ii) the second flag indicating that each of the image slicesin the coded video bitstream is included in one picture.

In an embodiment, the prediction information includes a third flagindicating whether each of the image slices in the coded video bitstreamis intra coded and included in one picture. The third flag is notincluded in the profile information.

In an embodiment, the third flag indicates that each of the image slicesin the coded video bitstream is intra coded and included in one picturebased on the second flag indicating that each of the image slices in thecoded video bitstream is included in one picture.

Aspects of the disclosure provide methods for video encoding/decoding.In the method, profile information for a plurality of image slices inprediction information of a coded video bitstream is decoded. Theprofile information includes profile identification information of aprofile in which each of the image slices in the coded video bitstreamis intra coded. Intra prediction on each of the image slices in thecoded video bitstream is performed. At least one image picture isreconstructed based on the intra prediction.

Aspects of the disclosure provide apparatuses for videoencoding/decoding. An apparatus includes processing circuitry thatdecodes profile information in prediction information of a coded videobitstream. The profile information includes a plurality of groups ofsyntax elements and indicates a profile for the coded video bitstream.The processing circuitry determines at least one of the plurality ofgroups of syntax elements based on the profile indicated in the profileinformation. The processing circuitry decodes syntax elements includedin the prediction information based on the determined at least one ofthe plurality of groups of syntax elements. The processing circuitryreconstructs at least one picture based on the decoded syntax elementsincluded in the prediction information.

In an embodiment, an order of the determined at least one of theplurality of groups of syntax elements for the profile is in accordancewith a predetermined order of the plurality of groups of syntax elementsin the profile information.

In an embodiment, byte alignment is checked for each of the plurality ofgroups of syntax elements in the profile information.

Aspects of the disclosure provide methods for video encoding/decoding.In the method, profile information in prediction information of a codedvideo bitstream is decoded. The profile information includes a pluralityof groups of syntax elements and indicates a profile for the coded videobitstream. At least one of the plurality of groups of syntax elements isdetermined based on the profile indicated in the profile information.Syntax elements included in the prediction information are decoded basedon the determined at least one of the plurality of groups of syntaxelements. At least one picture is reconstructed based on the decodedsyntax elements in the prediction information.

Aspects of the disclosure also provide non-transitory computer-readablemediums storing instructions which when executed by a computer for videodecoding cause the computer to perform any one or a combination of themethods for video decoding.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, the nature, and various advantages of the disclosedsubject matter will be more apparent from the following detaileddescription and the accompanying drawings in which:

FIG. 1A is a schematic illustration of an exemplary subset of intraprediction modes;

FIG. 1B is an illustration of exemplary intra prediction directions;

FIG. 1C is a schematic illustration of a current block and itssurrounding spatial merge candidates in one example;

FIG. 2 is a schematic illustration of a simplified block diagram of acommunication system in accordance with an embodiment;

FIG. 3 is a schematic illustration of a simplified block diagram of acommunication system in accordance with an embodiment;

FIG. 4 is a schematic illustration of a simplified block diagram of adecoder in accordance with an embodiment;

FIG. 5 is a schematic illustration of a simplified block diagram of anencoder in accordance with an embodiment;

FIG. 6 shows a block diagram of an encoder in accordance with anotherembodiment;

FIG. 7 shows a block diagram of a decoder in accordance with anotherembodiment;

FIG. 8 shows an exemplary flowchart in accordance with an embodiment;

FIG. 9 shows another exemplary flowchart in accordance with anembodiment;

and

FIG. 10 is a schematic illustration of a computer system in accordancewith an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

I. Video Decoder and Encoder Systems

FIG. 2 illustrates a simplified block diagram of a communication system(200) according to an embodiment of the present disclosure. Thecommunication system (200) includes a plurality of terminal devices thatcan communicate with each other, via, for example, a network (250). Forexample, the communication system (200) includes a first pair ofterminal devices (210) and (220) interconnected via the network (250).In the FIG. 2 example, the first pair of terminal devices (210) and(220) performs unidirectional transmission of data. For example, theterminal device (210) may code video data (e.g., a stream of videopictures that are captured by the terminal device (210)) fortransmission to the other terminal device (220) via the network (250).The encoded video data can be transmitted in the form of one or morecoded video bitstreams. The terminal device (220) may receive the codedvideo data from the network (250), decode the coded video data torecover the video pictures and display video pictures according to therecovered video data. Unidirectional data transmission may be common inmedia serving applications and the like.

In another example, the communication system (200) includes a secondpair of terminal devices (230) and (240) that performs bidirectionaltransmission of coded video data that may occur, for example, duringvideoconferencing. For bidirectional transmission of data, in anexample, each terminal device of the terminal devices (230) and (240)may code video data (e.g., a stream of video pictures that are capturedby the terminal device) for transmission to the other terminal device ofthe terminal devices (230) and (240) via the network (250). Eachterminal device of the terminal devices (230) and (240) also may receivethe coded video data transmitted by the other terminal device of theterminal devices (230) and (240), and may decode the coded video data torecover the video pictures and may display video pictures at anaccessible display device according to the recovered video data.

In the FIG. 2 example, the terminal devices (210), (220), (230) and(240) may be illustrated as servers, personal computers and smart phonesbut the principles of the present disclosure may be not so limited.Embodiments of the present disclosure find application with laptopcomputers, tablet computers, media players and/or dedicated videoconferencing equipment. The network (250) represents any number ofnetworks that convey coded video data among the terminal devices (210),(220), (230) and (240), including for example wireline (wired) and/orwireless communication networks. The communication network (250) mayexchange data in circuit-switched and/or packet-switched channels.Representative networks include telecommunications networks, local areanetworks, wide area networks and/or the Internet. For the purposes ofthe present discussion, the architecture and topology of the network(250) may be immaterial to the operation of the present disclosureunless explained herein below.

FIG. 3 illustrates, as an example for an application for the disclosedsubject matter, the placement of a video encoder and a video decoder ina streaming environment. The disclosed subject matter can be equallyapplicable to other video enabled applications, including, for example,video conferencing, digital TV, storing of compressed video on digitalmedia including CD, DVD, memory stick, and the like.

A streaming system may include a capture subsystem (313) that caninclude a video source (301), for example a digital camera, creating forexample a stream of video pictures (302) that are uncompressed. In anexample, the stream of video pictures (302) includes samples that aretaken by the digital camera. The stream of video pictures (302),depicted as a bold line to emphasize a high data volume when compared toencoded video data (304) (or coded video bitstreams), can be processedby an electronic device (320) that includes a video encoder (303)coupled to the video source (301). The video encoder (303) can includehardware, software, or a combination thereof to enable or implementaspects of the disclosed subject matter as described in more detailbelow. The encoded video data (304) (or encoded video bitstream (304)),depicted as a thin line to emphasize the lower data volume when comparedto the stream of video pictures (302), can be stored on a streamingserver (305) for future use. One or more streaming client subsystems,such as client subsystems (306) and (308) in FIG. 3 can access thestreaming server (305) to retrieve copies (307) and (309) of the encodedvideo data (304). A client subsystem (306) can include a video decoder(310), for example, in an electronic device (330). The video decoder(310) decodes the incoming copy (307) of the encoded video data andcreates an outgoing stream of video pictures (311) that can be renderedon a display (312) (e.g., display screen) or other rendering device (notdepicted). In some streaming systems, the encoded video data (304),(307), and (309) (e.g., video bitstreams) can be encoded according tocertain video coding/compression standards. Examples of those standardsinclude ITU-T Recommendation H.265. In an example, a video codingstandard under development is informally known as VVC. The disclosedsubject matter may be used in the context of VVC.

It is noted that the electronic devices (320) and (330) can includeother components (not shown). For example, the electronic device (320)can include a video decoder (not shown) and the electronic device (330)can include a video encoder (not shown) as well.

FIG. 4 shows a block diagram of a video decoder (410) according to anembodiment of the present disclosure. The video decoder (410) can beincluded in an electronic device (430). The electronic device (430) caninclude a receiver (431) (e.g., receiving circuitry). The video decoder(410) can be used in the place of the video decoder (310) in the FIG. 3example.

The receiver (431) may receive one or more coded video sequences to bedecoded by the video decoder (410); in the same or another embodiment,one coded video sequence at a time, where the decoding of each codedvideo sequence is independent from other coded video sequences. Thecoded video sequence may be received from a channel (401), which may bea hardware/software link to a storage device which stores the encodedvideo data. The receiver (431) may receive the encoded video data withother data, for example, coded audio data and/or ancillary data streams,that may be forwarded to their respective using entities (not depicted).The receiver (431) may separate the coded video sequence from the otherdata. To combat network jitter, a buffer memory (415) may be coupled inbetween the receiver (431) and an entropy decoder/parser (420) (“parser(420)” henceforth). In certain applications, the buffer memory (415) ispart of the video decoder (410). In others, it can be outside of thevideo decoder (410) (not depicted). In still others, there can be abuffer memory (not depicted) outside of the video decoder (410), forexample to combat network jitter, and in addition another buffer memory(415) inside the video decoder (410), for example to handle playouttiming. When the receiver (431) is receiving data from a store/forwarddevice of sufficient bandwidth and controllability, or from anisosynchronous network, the buffer memory (415) may not be needed, orcan be small. For use on best effort packet networks such as theInternet, the buffer memory (415) may be required, can be comparativelylarge and can be advantageously of adaptive size, and may at leastpartially be implemented in an operating system or similar elements (notdepicted) outside of the video decoder (410).

The video decoder (410) may include the parser (420) to reconstructsymbols (421) from the coded video sequence. Categories of those symbolsinclude information used to manage operation of the video decoder (410),and potentially information to control a rendering device such as arender device (412) (e.g., a display screen) that is not an integralpart of the electronic device (430) but can be coupled to the electronicdevice (430), as was shown in FIG. 4. The control information for therendering device(s) may be in the form of Supplemental EnhancementInformation (SEI messages) or Video Usability Information (VUI)parameter set fragments (not depicted). The parser (420) mayparse/entropy-decode the coded video sequence that is received. Thecoding of the coded video sequence can be in accordance with a videocoding technology or standard, and can follow various principles,including variable length coding, Huffman coding, arithmetic coding withor without context sensitivity, and so forth. The parser (420) mayextract from the coded video sequence, a set of subgroup parameters forat least one of the subgroups of pixels in the video decoder, based uponat least one parameter corresponding to the group. Subgroups can includeGroups of Pictures (GOPs), pictures, tiles, slices, macroblocks, CodingUnits (CUs), blocks, Transform Units (TUs), Prediction Units (PUs) andso forth. The parser (420) may also extract from the coded videosequence information such as transform coefficients, quantizer parametervalues, MVs, and so forth.

The parser (420) may perform an entropy decoding/parsing operation onthe video sequence received from the buffer memory (415), so as tocreate symbols (421).

Reconstruction of the symbols (421) can involve multiple different unitsdepending on the type of the coded video picture or parts thereof (suchas: inter and intra picture, inter and intra block), and other factors.Which units are involved, and how, can be controlled by the subgroupcontrol information that was parsed from the coded video sequence by theparser (420). The flow of such subgroup control information between theparser (420) and the multiple units below is not depicted for clarity.

Beyond the functional blocks already mentioned, the video decoder (410)can be conceptually subdivided into a number of functional units asdescribed below. In a practical implementation operating undercommercial constraints, many of these units interact closely with eachother and can, at least partly, be integrated into each other. However,for the purpose of describing the disclosed subject matter, theconceptual subdivision into the functional units below is appropriate.

A first unit is the scaler/inverse transform unit (451). Thescaler/inverse transform unit (451) receives a quantized transformcoefficient as well as control information, including which transform touse, block size, quantization factor, quantization scaling matrices,etc. as symbol(s) (421) from the parser (420). The scaler/inversetransform unit (451) can output blocks comprising sample values that canbe input into aggregator (455).

In some cases, the output samples of the scaler/inverse transform (451)can pertain to an intra coded block; that is: a block that is not usingpredictive information from previously reconstructed pictures, but canuse predictive information from previously reconstructed parts of thecurrent picture. Such predictive information can be provided by an intrapicture prediction unit (452). In some cases, the intra pictureprediction unit (452) generates a block of the same size and shape ofthe block under reconstruction, using surrounding already reconstructedinformation fetched from the current picture buffer (458). The currentpicture buffer (458) buffers, for example, partly reconstructed currentpicture and/or fully reconstructed current picture. The aggregator(455), in some cases, adds, on a per sample basis, the predictioninformation that the intra prediction unit (452) has generated to theoutput sample information as provided by the scaler/inverse transformunit (451).

In other cases, the output samples of the scaler/inverse transform unit(451) can pertain to an inter coded, and potentially motion compensatedblock. In such a case, a motion compensation prediction unit (453) canaccess reference picture memory (457) to fetch samples used forprediction. After motion compensating the fetched samples in accordancewith the symbols (421) pertaining to the block, these samples can beadded by the aggregator (455) to the output of the scaler/inversetransform unit (451) (in this case called the residual samples orresidual signal) so as to generate output sample information. Theaddresses within the reference picture memory (457) from where themotion compensation prediction unit (453) fetches prediction samples canbe controlled by MVs, available to the motion compensation predictionunit (453) in the form of symbols (421) that can have, for example X, Y,and reference picture components. Motion compensation also can includeinterpolation of sample values as fetched from the reference picturememory (457) when sub-sample exact MVs are in use, MV predictionmechanisms, and so forth.

The output samples of the aggregator (455) can be subject to variousloop filtering techniques in the loop filter unit (456). Videocompression technologies can include in-loop filter technologies thatare controlled by parameters included in the coded video sequence (alsoreferred to as coded video bitstream) and made available to the loopfilter unit (456) as symbols (421) from the parser (420), but can alsobe responsive to meta-information obtained during the decoding ofprevious (in decoding order) parts of the coded picture or coded videosequence, as well as responsive to previously reconstructed andloop-filtered sample values.

The output of the loop filter unit (456) can be a sample stream that canbe output to the render device (412) as well as stored in the referencepicture memory (457) for use in future inter-picture prediction.

Certain coded pictures, once fully reconstructed, can be used asreference pictures for future prediction. For example, once a codedpicture corresponding to a current picture is fully reconstructed andthe coded picture has been identified as a reference picture (by, forexample, the parser (420)), the current picture buffer (458) can becomea part of the reference picture memory (457), and a fresh currentpicture buffer can be reallocated before commencing the reconstructionof the following coded picture.

The video decoder (410) may perform decoding operations according to apredetermined video compression technology in a standard, such as ITU-TRec. H.265. The coded video sequence may conform to a syntax specifiedby the video compression technology or standard being used, in the sensethat the coded video sequence adheres to both the syntax of the videocompression technology or standard and the profiles as documented in thevideo compression technology or standard. Specifically, a profile canselect certain tools as the only tools available for use under thatprofile from all the tools available in the video compression technologyor standard. Also necessary for compliance can be that the complexity ofthe coded video sequence is within bounds as defined by the level of thevideo compression technology or standard. In some cases, levels restrictthe maximum picture size, maximum frame rate, maximum reconstructionsample rate (measured in, for example megasamples per second), maximumreference picture size, and so on. Limits set by levels can, in somecases, be further restricted through Hypothetical Reference Decoder(HRD) specifications and metadata for HRD buffer management signaled inthe coded video sequence.

In an embodiment, the receiver (431) may receive additional (redundant)data with the encoded video. The additional data may be included as partof the coded video sequence(s). The additional data may be used by thevideo decoder (410) to properly decode the data and/or to moreaccurately reconstruct the original video data. Additional data can bein the form of, for example, temporal, spatial, or signal noise ratio(SNR) enhancement layers, redundant slices, redundant pictures, forwarderror correction codes, and so on.

FIG. 5 shows a block diagram of a video encoder (503) according to anembodiment of the present disclosure. The video encoder (503) isincluded in an electronic device (520). The electronic device (520)includes a transmitter (540) (e.g., transmitting circuitry). The videoencoder (503) can be used in the place of the video encoder (303) in theFIG. 3 example.

The video encoder (503) may receive video samples from a video source(501) (that is not part of the electronic device (520) in the FIG. 5example) that may capture video image(s) to be coded by the videoencoder (503). In another example, the video source (501) is a part ofthe electronic device (520).

The video source (501) may provide the source video sequence to be codedby the video encoder (503) in the form of a digital video sample streamthat can be of any suitable bit depth (for example: 8 bit, 10 bit, 12bit, . . . ), any colorspace (for example, BT.601 Y CrCB, RGB, . . . ),and any suitable sampling structure (for example Y CrCb 4:2:0, Y CrCb4:4:4). In a media serving system, the video source (501) may be astorage device storing previously prepared video. In a videoconferencingsystem, the video source (501) may be a camera that captures local imageinformation as a video sequence. Video data may be provided as aplurality of individual pictures that impart motion when viewed insequence. The pictures themselves may be organized as a spatial array ofpixels, wherein each pixel can comprise one or more samples depending onthe sampling structure, color space, etc. in use. A person skilled inthe art can readily understand the relationship between pixels andsamples. The description below focuses on samples.

According to an embodiment, the video encoder (503) may code andcompress the pictures of the source video sequence into a coded videosequence (543) in real time or under any other time constraints asrequired by the application. Enforcing appropriate coding speed is onefunction of a controller (550). In some embodiments, the controller(550) controls other functional units as described below and isfunctionally coupled to the other functional units. The coupling is notdepicted for clarity. Parameters set by the controller (550) can includerate control related parameters (picture skip, quantizer, lambda valueof rate-distortion optimization techniques, . . . ), picture size, groupof pictures (GOP) layout, maximum MV allowed reference area, and soforth. The controller (550) can be configured to have other suitablefunctions that pertain to the video encoder (503) optimized for acertain system design.

In some embodiments, the video encoder (503) is configured to operate ina coding loop. As an oversimplified description, in an example, thecoding loop can include a source coder (530) (e.g., responsible forcreating symbols, such as a symbol stream, based on an input picture tobe coded, and a reference picture(s)), and a (local) decoder (533)embedded in the video encoder (503). The decoder (533) reconstructs thesymbols to create the sample data in a similar manner as a (remote)decoder also would create (as any compression between symbols and codedvideo bitstream is lossless in the video compression technologiesconsidered in the disclosed subject matter). The reconstructed samplestream (sample data) is input to the reference picture memory (534). Asthe decoding of a symbol stream leads to bit-exact results independentof decoder location (local or remote), the content in the referencepicture memory (534) is also bit exact between the local encoder andremote encoder. In other words, the prediction part of an encoder “sees”as reference picture samples exactly the same sample values as a decoderwould “see” when using prediction during decoding. This fundamentalprinciple of reference picture synchronicity (and resulting drift, ifsynchronicity cannot be maintained, for example because of channelerrors) is used in some related arts as well.

The operation of the “local” decoder (533) can be the same as of a“remote” decoder, such as the video decoder (410), which has alreadybeen described in detail above in conjunction with FIG. 4. Brieflyreferring also to FIG. 4, however, as symbols are available andencoding/decoding of symbols to a coded video sequence by an entropycoder (545) and the parser (420) can be lossless, the entropy decodingparts of the video decoder (410), including the buffer memory (415) andthe parser (420) may not be fully implemented in the local decoder(533).

An observation that can be made at this point is that any decodertechnology except the parsing/entropy decoding that is present in adecoder also necessarily needs to be present, in substantially identicalfunctional form, in a corresponding encoder. For this reason, thedisclosed subject matter focuses on decoder operation. The descriptionof encoder technologies can be abbreviated as they are the inverse ofthe comprehensively described decoder technologies. Only in certainareas a more detail description is required and provided below.

During operation, in some examples, the source coder (530) may performmotion compensated predictive coding, which codes an input picturepredictively with reference to one or more previously-coded picture fromthe video sequence that were designated as “reference pictures”. In thismanner, the coding engine (532) codes differences between pixel blocksof an input picture and pixel blocks of reference picture(s) that may beselected as prediction reference(s) to the input picture.

The local video decoder (533) may decode coded video data of picturesthat may be designated as reference pictures, based on symbols createdby the source coder (530). Operations of the coding engine (532) mayadvantageously be lossy processes. When the coded video data may bedecoded at a video decoder (not shown in FIG. 5), the reconstructedvideo sequence typically may be a replica of the source video sequencewith some errors. The local video decoder (533) replicates decodingprocesses that may be performed by the video decoder on referencepictures and may cause reconstructed reference pictures to be stored inthe reference picture cache (534). In this manner, the video encoder(503) may store copies of reconstructed reference pictures locally thathave common content as the reconstructed reference pictures that will beobtained by a far-end video decoder (absent transmission errors).

The predictor (535) may perform prediction searches for the codingengine (532). That is, for a new picture to be coded, the predictor(535) may search the reference picture memory (534) for sample data (ascandidate reference pixel blocks) or certain metadata such as referencepicture MVs, block shapes, and so on, that may serve as an appropriateprediction reference for the new pictures. The predictor (535) mayoperate on a sample block-by-pixel block basis to find appropriateprediction references. In some cases, as determined by search resultsobtained by the predictor (535), an input picture may have predictionreferences drawn from multiple reference pictures stored in thereference picture memory (534).

The controller (550) may manage coding operations of the source coder(530), including, for example, setting of parameters and subgroupparameters used for encoding the video data.

Output of all aforementioned functional units may be subjected toentropy coding in the entropy coder (545). The entropy coder (545)translates the symbols as generated by the various functional units intoa coded video sequence, by lossless compressing the symbols according totechnologies such as Huffman coding, variable length coding, arithmeticcoding, and so forth.

The transmitter (540) may buffer the coded video sequence(s) as createdby the entropy coder (545) to prepare for transmission via acommunication channel (560), which may be a hardware/software link to astorage device which would store the encoded video data. The transmitter(540) may merge coded video data from the video coder (503) with otherdata to be transmitted, for example, coded audio data and/or ancillarydata streams (sources not shown).

The controller (550) may manage operation of the video encoder (503).During coding, the controller (550) may assign to each coded picture acertain coded picture type, which may affect the coding techniques thatmay be applied to the respective picture. For example, pictures oftenmay be assigned as one of the following picture types:

An Intra Picture (I picture) may be one that may be coded and decodedwithout using any other picture in the sequence as a source ofprediction. Some video codecs allow for different types of intrapictures, including, for example Independent Decoder Refresh (“IDR”)Pictures. A person skilled in the art is aware of those variants of Ipictures and their respective applications and features.

A predictive picture (P picture) may be one that may be coded anddecoded using intra prediction or inter prediction using at most one MVand reference index to predict the sample values of each block.

A bi-directionally predictive picture (B Picture) may be one that may becoded and decoded using intra prediction or inter prediction using atmost two MVs and reference indices to predict the sample values of eachblock. Similarly, multiple-predictive pictures can use more than tworeference pictures and associated metadata for the reconstruction of asingle block.

Source pictures commonly may be subdivided spatially into a plurality ofsample blocks (for example, blocks of 4×4, 8×8, 4×8, or 16×16 sampleseach) and coded on a block-by-block basis. Blocks may be codedpredictively with reference to other (already coded) blocks asdetermined by the coding assignment applied to the blocks' respectivepictures. For example, blocks of I pictures may be codednon-predictively or they may be coded predictively with reference toalready coded blocks of the same picture (spatial prediction or intraprediction). Pixel blocks of P pictures may be coded predictively, viaspatial prediction or via temporal prediction with reference to onepreviously coded reference picture. Blocks of B pictures may be codedpredictively, via spatial prediction or via temporal prediction withreference to one or two previously coded reference pictures.

The video encoder (503) may perform coding operations according to apredetermined video coding technology or standard, such as ITU-T Rec.H.265. In its operation, the video encoder (503) may perform variouscompression operations, including predictive coding operations thatexploit temporal and spatial redundancies in the input video sequence.The coded video data, therefore, may conform to a syntax specified bythe video coding technology or standard being used.

In an embodiment, the transmitter (540) may transmit additional datawith the encoded video. The source coder (530) may include such data aspart of the coded video sequence. Additional data may comprisetemporal/spatial/SNR enhancement layers, other forms of redundant datasuch as redundant pictures and slices, SEI messages, VUI parameter setfragments, and so on.

A video may be captured as a plurality of source pictures (videopictures) in a temporal sequence. Intra-picture prediction (oftenabbreviated to intra prediction) makes use of spatial correlation in agiven picture, and inter-picture prediction makes uses of the (temporalor other) correlation between the pictures. In an example, a specificpicture under encoding/decoding, which is referred to as a currentpicture, is partitioned into blocks. When a block in the current pictureis similar to a reference block in a previously coded and still bufferedreference picture in the video, the block in the current picture can becoded by a vector that is referred to as a MV. The MV points to thereference block in the reference picture, and can have a third dimensionidentifying the reference picture, in case multiple reference picturesare in use.

In some embodiments, a bi-prediction technique can be used in theinter-picture prediction. According to the bi-prediction technique, tworeference pictures, such as a first reference picture and a secondreference picture that are both prior in decoding order to the currentpicture in the video (but may be in the past and future, respectively,in display order) are used. A block in the current picture can be codedby a first MV that points to a first reference block in the firstreference picture, and a second MV that points to a second referenceblock in the second reference picture. The block can be predicted by acombination of the first reference block and the second reference block.

Further, a merge mode technique can be used in the inter-pictureprediction to improve coding efficiency.

According to some embodiments of the disclosure, predictions, such asinter-picture predictions and intra-picture predictions are performed inthe unit of blocks. For example, according to the HEVC standard, apicture in a sequence of video pictures is partitioned into coding treeunits (CTU) for compression, the CTUs in a picture have the same size,such as 64×64 pixels, 32×32 pixels, or 16×16 pixels. In general, a CTUincludes three coding tree blocks (CTBs), which are one luma CTB and twochroma CTBs. Each CTU can be recursively quad-tree split into one ormultiple coding units (CUs). For example, a CTU of 64×64 pixels can besplit into one CU of 64×64 pixels, or 4 CUs of 32×32 pixels, or 16 CUsof 16×16 pixels. In an example, each CU is analyzed to determine aprediction type for the CU, such as an inter prediction type or an intraprediction type. The CU is split into one or more prediction units (PUs)depending on the temporal and/or spatial predictability. Generally, eachPU includes a luma prediction block (PB), and two chroma PBs. In anembodiment, a prediction operation in coding (encoding/decoding) isperformed in the unit of a prediction block. Using a luma predictionblock as an example of a prediction block, the prediction block includesa matrix of values (e.g., luma values) for pixels, such as 8×8 pixels,16×16 pixels, 8×16 pixels, 16×8 pixels, and the like.

FIG. 6 shows a diagram of a video encoder (603) according to anotherembodiment of the disclosure. The video encoder (603) is configured toreceive a processing block (e.g., a prediction block) of sample valueswithin a current video picture in a sequence of video pictures, andencode the processing block into a coded picture that is part of a codedvideo sequence. In an example, the video encoder (603) is used in theplace of the video encoder (303) in the FIG. 3 example.

In an HEVC example, the video encoder (603) receives a matrix of samplevalues for a processing block, such as a prediction block of 8×8samples, and the like. The video encoder (603) determines whether theprocessing block is best coded using intra mode, inter mode, orbi-prediction mode using, for example, rate-distortion optimization.When the processing block is to be coded in intra mode, the videoencoder (603) may use an intra prediction technique to encode theprocessing block into the coded picture; and when the processing blockis to be coded in inter mode or bi-prediction mode, the video encoder(603) may use an inter prediction or bi-prediction technique,respectively, to encode the processing block into the coded picture. Incertain video coding technologies, merge mode can be an inter pictureprediction submode where the MV is derived from one or more MVpredictors without the benefit of a coded MV component outside thepredictors. In certain other video coding technologies, a MV componentapplicable to the subject block may be present. In an example, the videoencoder (603) includes other components, such as a mode decision module(not shown) to determine the mode of the processing blocks.

In the FIG. 6 example, the video encoder (603) includes the interencoder (630), an intra encoder (622), a residue calculator (623), aswitch (626), a residue encoder (624), a general controller (621), andan entropy encoder (625) coupled together as shown in FIG. 6.

The inter encoder (630) is configured to receive the samples of thecurrent block (e.g., a processing block), compare the block to one ormore reference blocks in reference pictures (e.g., blocks in previouspictures and later pictures), generate inter prediction information(e.g., description of redundant information according to inter encodingtechnique, MVs, merge mode information), and calculate inter predictionresults (e.g., prediction block) based on the inter predictioninformation using any suitable technique. In some examples, thereference pictures are decoded reference pictures that are decoded basedon the encoded video information.

The intra encoder (622) is configured to receive the samples of thecurrent block (e.g., a processing block), in some cases compare theblock to blocks already coded in the same picture, generate quantizedcoefficients after transform, and in some cases also intra predictioninformation (e.g., an intra prediction direction information accordingto one or more intra encoding techniques). In an example, the intraencoder (622) also calculates intra prediction results (e.g., predictionblock) based on the intra prediction information and reference blocks inthe same picture.

The general controller (621) is configured to determine general controldata and control other components of the video encoder (603) based onthe general control data. In an example, the general controller (621)determines the mode of the block, and provides a control signal to theswitch (626) based on the mode. For example, when the mode is the intramode, the general controller (621) controls the switch (626) to selectthe intra mode result for use by the residue calculator (623), andcontrols the entropy encoder (625) to select the intra predictioninformation and include the intra prediction information in thebitstream; and when the mode is the inter mode, the general controller(621) controls the switch (626) to select the inter prediction resultfor use by the residue calculator (623), and controls the entropyencoder (625) to select the inter prediction information and include theinter prediction information in the bitstream.

The residue calculator (623) is configured to calculate a difference(residue data) between the received block and prediction resultsselected from the intra encoder (622) or the inter encoder (630). Theresidue encoder (624) is configured to operate based on the residue datato encode the residue data to generate the transform coefficients. In anexample, the residue encoder (624) is configured to convert the residuedata from a spatial domain to a frequency domain, and generate thetransform coefficients. The transform coefficients are then subject toquantization processing to obtain quantized transform coefficients. Invarious embodiments, the video encoder (603) also includes a residuedecoder (628). The residue decoder (628) is configured to performinverse-transform, and generate the decoded residue data. The decodedresidue data can be suitably used by the intra encoder (622) and theinter encoder (630). For example, the inter encoder (630) can generatedecoded blocks based on the decoded residue data and inter predictioninformation, and the intra encoder (622) can generate decoded blocksbased on the decoded residue data and the intra prediction information.The decoded blocks are suitably processed to generate decoded picturesand the decoded pictures can be buffered in a memory circuit (not shown)and used as reference pictures in some examples.

The entropy encoder (625) is configured to format the bitstream toinclude the encoded block. The entropy encoder (625) is configured toinclude various information according to a suitable standard such asHEVC. In an example, the entropy encoder (625) is configured to includethe general control data, the selected prediction information (e.g.,intra prediction information or inter prediction information), theresidue information, and other suitable information in the bitstream.Note that, according to the disclosed subject matter, when coding ablock in the merge submode of either inter mode or bi-prediction mode,there is no residue information.

FIG. 7 shows a diagram of a video decoder (710) according to anotherembodiment of the disclosure. The video decoder (710) is configured toreceive coded pictures that are part of a coded video sequence, anddecode the coded pictures to generate reconstructed pictures. In anexample, the video decoder (710) is used in the place of the videodecoder (310) in the FIG. 3 example.

In the FIG. 7 example, the video decoder (710) includes an entropydecoder (771), an inter decoder (780), a residue decoder (773), areconstruction module (774), and an intra decoder (772) coupled togetheras shown in FIG. 7.

The entropy decoder (771) can be configured to reconstruct, from thecoded picture, certain symbols that represent the syntax elements ofwhich the coded picture is made up. Such symbols can include, forexample, the mode in which a block is coded (such as, for example, intramode, inter mode, bi-predicted mode, the latter two in merge submode oranother submode), prediction information (such as, for example, intraprediction information or inter prediction information) that canidentify certain sample or metadata that is used for prediction by theintra decoder (772) or the inter decoder (780), respectively, residualinformation in the form of, for example, quantized transformcoefficients, and the like. In an example, when the prediction mode isinter or bi-predicted mode, the inter prediction information is providedto the inter decoder (780); and when the prediction type is the intraprediction type, the intra prediction information is provided to theintra decoder (772). The residual information can be subject to inversequantization and is provided to the residue decoder (773).

The inter decoder (780) is configured to receive the inter predictioninformation, and generate inter prediction results based on the interprediction information.

The intra decoder (772) is configured to receive the intra predictioninformation, and generate prediction results based on the intraprediction information.

The residue decoder (773) is configured to perform inverse quantizationto extract de-quantized transform coefficients, and process thede-quantized transform coefficients to convert the residual from thefrequency domain to the spatial domain. The residue decoder (773) mayalso require certain control information (to include the QuantizerParameter (QP)), and that information may be provided by the entropydecoder (771) (data path not depicted as this may be low volume controlinformation only).

The reconstruction module (774) is configured to combine, in the spatialdomain, the residual as output by the residue decoder (773) and theprediction results (as output by the inter or intra prediction modulesas the case may be) to form a reconstructed block, that may be part ofthe reconstructed picture, which in turn may be part of thereconstructed video. It is noted that other suitable operations, such asa deblocking operation and the like, can be performed to improve thevisual quality.

It is noted that the video encoders (303), (503), and (603), and thevideo decoders (310), (410), and (710) can be implemented using anysuitable technique. In an embodiment, the video encoders (303), (503),and (603), and the video decoders (310), (410), and (710) can beimplemented using one or more integrated circuits. In anotherembodiment, the video encoders (303), (503), and (603), and the videodecoders (310), (410), and (710) can be implemented using one or moreprocessors that execute software instructions.

II. Exemplary High Level Syntax Elements

Table 1 shows exemplary sequence parameter set (SPS) syntax elements insome related examples such as VVC. Both syntax elements related to intracoding and inter coding are included in Table 1. It is noted that for anintra profile which only includes intra slices, inter coding syntaxelements may be present in the SPS but are not used in a decodingprocess of the intra profile. The situation also applies to any stillpicture profile. That is, for a still picture profile which onlyincludes intra slice(s), inter coding syntax elements are not used in adecoding process of the still profile.

TABLE 1 Sequence parameter set raw byte sequence payload (RBSP) syntaxseq_parameter_set_rbsp( ) { Descriptor  sps_seq_parameter_set_id u(4) sps_video_parameter_set_id u(4)  sps_max_sublayers_minus1 u(3) sps_reserved_zero_4bits u(4)  sps_ptl_dpb_hrd_params_present_flag u(1) if( sps_ptl_dpb_hrd_params_present_flag )   profile_tier_level( 1,sps_max_sublayers_minus1 )  gdr_enabled_flag u(1)  chroma_format_idcu(2)  if( chroma_format_idc = = 3 )   separate_colour_plane_flag u(1) res_change_in_clvs_allowed_flag u(1)  pic_width_max_in_luma_samplesue(v)  pic_height_max_iniuma_samples ue(v)  sps_conformance_window_flagu(1)  if( sps_conformance_window_flag ) {   sps_conf_win_left_offsetue(v)   sps_conf_win_right_offset ue(v)   sps_conf_win_top_offset ue(v)  sps_conf_win_bottom_offset ue(v)  }  sps_log2_ctu_size_minus5 u(2) subpic_info_present_flag u(1)  if( subpic_info_present_flag ) {  sps_num_subpics_minus1 ue(v)   sps_independent_subpics_flag u(1)  for( i = 0; sps_num_subpics_minus1 > 0 &&   i <=sps_num_subpics_minus1; i++) {    if( i > 0 && pic_width_max_in_luma_   samples > CtbSizeY )     subpic_ctu_top_left_x[ i ] u(v)    if( i > 0&& pic_height_max_in_luma_    samples > CtbSizeY ) {    subpic_ctu_top_left_y[ i ] u(v)    if( i < sps_num_subpics_minus1 &&     pic_width_max_in_luma_samples > CtbSizeY )     subpic_width_minus1[i ] u(v)    if( i < sps_num_subpics_minus1 &&     pic_height_max_in_luma_samples >      CtbSizeY )    subpic_height_minus1[ i ] u(v)    if( !sps_independent_subpics_flag) {     subpic_treated_as_pic_flag[ i ] u(1)    loop_filter_across_subpic_enabled_flag[ i ] u(1)    }   }  sps_subpic_id_len_minus1 ue(v)  subpic_id_mapping_explicitly_signalled_flag u(1)   if(subpic_id_mapping_explicitly_signalled_flag ) {   subpic_id_mapping_in_sps_flag u(1)    if(subpic_id_mapping_in_sps_flag )     for( i = 0; i <=sps_num_subpics_minus1; i++)      sps_subpic_id[ i ] u(v)   }  } bit_depth_minus8 ue(v)  sps_entropy_coding_sync_enabled_flag u(1)  if(sps_entropy_coding_sync_enabled_flag )  sps_wpp_entry_point_offsets_present_flag u(1)  sps_weighted_pred_flagu(1)  sps_weighted_bipred_flag u(1)  log2_max_pic_order_cnt_lsb_minus4u(4)  sps_poc_msb_flag u(1)  if( sps_poc_msb_flag )   poc_msb_len_minus1ue(v)  num_extra_ph_bits_bytes u(2)  extra_ph_bits_struct(num_extra_ph_bits_bytes )  num_extra_sh_bits_bytes u(2) extra_sh_bits_struct( num_extra_sh_bits_bytes )  if(sps_max_sublayers_minus1 > 0 )   sps_sublayer_dpb_params_flag u(1)  if(sps_ptl_dpb_hrd_params_present_flag )   dpb_parameters(sps_max_sublayers_minus1,   sps_sublayer_dpb_params_flag ) long_term_ref_pics_flag u(1)  inter_layer_ref_pics_present_flag u(1) sps_idr_rpl_present_flag u(1)  rpl1_same_as_rpl0_flag u(1)  for( i = 0;i < rpl1_same_as_rpl0_flag ? 1 : 2; i++ ) {    num_ref_pic_lists_in_sps[i ] ue(v)    for( j = 0; j < num_ref_pic_lists_in_sps[ i ]; j++)   ref_pic_list_struct( i, j )  }  if( ChromaArrayType != 0 )  qtbtt_dual_tree_intra_flag u(1) log2_min_luma_coding_block_size_minus2 ue(v) partition_constraints_override_enabled_flag u(1) sps_log2_diff_min_qt_min_cb_intra_slice_luma ue(v) sps_max_mtt_hierarchy_depth_intra_slice_luma ue(v)  if(sps_max_mtt_hierarchy_depth_intra_slice_luma  != 0 ) {  sps_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)  sps_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)  } sps_log2_diff_min_qt_min_cb_inter_slice ue(v) sps_max_mtt_hierarchy_depth_inter_slice ue(v)  if(sps_max_mtt_hierarchy_depth_inter_slice != 0 ) {  sps_log2_diff_max_bt_min_qt_inter_slice ue(v)  sps_log2_diff_max_tt_min_qt_inter_slice ue(v)  }  if(qtbtt_dual_tree_intra_flag ) {  sps_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)  sps_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)   if(sps_max_mtt_hierarchy_depth_intra_   slice_chroma != 0 ) {   sps_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v)   sps_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)   }  } sps_max_luma_transform_size_64_flag u(1)  if( ChromaArrayType != 0 ) {  sps_joint_cbcr_enabled_flag u(1)   same_qp_table_for_chroma u(1)  numQpTables = same_qp_table_for_chroma ?   1 : (sps_joint_cbcr_enabled_flag ? 3 : 2 )   for( i = 0; i < numQpTables; i++) {    qp_table_start_minus26[ i ] se(v)   num_points_in_qp_table_minus1[ i ] ue(v)    for( j = 0; j <=num_points_in_qp_table_    minus1[ i ]; j++ ) {    delta_qp_in_val_minus1[ i ][ j ] ue(v)     delta_qp_diff_val[ i ][ j] ue(v)    }   }  }  sps_sao_enabled_flag u(1)  sps_alf_enabled_flagu(1)  if( sps_alf_enabled_flag && ChromaArrayType != 0 )   sps_ccalfenabled_flag u(1)  sps_transform_skip_enabled_flag u(1)  if(sps_transform_skip_enabled_flag ) {  log2_transform_skip_max_size_minus2 ue(v)   sps_bdpcm_enabled_flagu(1)  }  sps_ref_wraparound_enabled_flag u(1) sps_temporal_mvp_enabled_flag u(1)  if( sps_temporal_mvp_enabled_flag )  sps_sbtmvp_enabled_flag u(1)  sps_amvr_enabled_flag u(1) sps_bdof_enabled_flag u(1)  if( sps_bdof_enabled_flag )  sps_bdof_pic_present_flag u(1)  sps_smvd_enabled_flag u(1) sps_dmvr_enabled_flag u(1)  if( sps_dmvr_enabled_flag)  sps_dmvr_pic_present_flag u(1)  sps_mmvd_enabled_flag u(1) sps_isp_enabled_flag u(1)  sps_mrl_enabled_flag u(1) sps_mip_enabled_flag u(1)  if( ChromaArrayType != 0 )  sps_cclm_enabled_flag u(1)  if( chroma_format_idc = = 1 ) {  sps_chroma_horizontal_collocated_flag u(1)  sps_chroma_vertical_collocated_flag u(1)  }  sps_mts_enabled_flag u(1) if( sps_mts_enabled_flag ) {   sps_explicit_mts_intra_enabled_flag u(1)  sps_explicit_mts_inter_enabled_flag u(1)  } six_minus_max_num_merge_cand ue(v)  sps_sbt_enabled_flag u(1) sps_affme_enabled_flag u(1)  if( sps_affine_enabled_flag ) {  five_minus_max_num_subblock_merge_cand ue(v)   sps_affme_type_flagu(1)   if( sps_amvr_enabled_flag )    sps_affine_amvr_enabled_flag u(1)  sps_affine_prof_enabled_flag u(1)   if sps_affine_prof_enabled_flag )   sps_prof_pic_present_flag u(1)  }  sps_palette_enabled_flag u(1)  if(ChromaArrayType = = 3 &&  !sps_max_luma_transform_size_64_flag )  sps_act_enabled_flag u(1)  if( sps_transform_skip_enabled_flag || sps_palette_enabled_flag )   min_qp_prime_ts_minus4 ue(v) sps_bcw_enabled_flag u(1)  sps_ibc_enabled_flag u(1)  if(sps_ibc_enabled_flag )   six_minus_max_num_ibc_merge_cand ue(v) sps_ciip_enabled_flag u(1)  if( sps_mmvd_enabled_flag )  sps_fpel_mmvd_enabled_flag u(1)  if( MaxNumMergeCand >= 2 ) {  sps_gpm_enabled_flag u(1)   if( sps_gpm_enabled_flag &&  MaxNumMergeCand >= 3 )    max_num_merge_cand_minus_max_num_gpm_candue(v)  }  sps_lmcs_enabled_flag u(1)  sps_lfnst_enabled_flag u(1) sps_ladf_enabled_flag u(1)  if( sps_ladf enabled_flag ) {  sps_num_ladf_intervals_minus2 u(2)  sps_ladf_lowest_interval_qp_offset se(v)   for( i = 0; i <sps_num_ladf_intervals_minus2 +   1; i++ ) {    sps_ladf_qp_offset[ i ]se(v)    sps_ladf_delta_threshold_minus1[ i ] ue(v)   }  } log2_parallel_merge_level_minus2 ue(v) sps_explicit_scaling_list_enabled_flag u(1)  sps_dep_quant_enabled_flagu(1)  if( !sps_dep_quant_enabled_flag )  sps_sign_data_hiding_enabled_flag u(1) sps_virtual_boundaries_enabled_flag u(1)  if(sps_virtual_boundaries_enabled_flag ) {  sps_virtual_boundaries_present_flag u(1)   if(sps_virtual_boundaries_present_flag ) {   sps_num_ver_virtual_boundaries u(2)    for( i = 0; i <sps_num_ver_virtual_boundaries; i++ )     sps_virtual_boundaries_pos_x[i ] u(13)    sps_num_hor_virtual_boundaries u(2)    for( i = 0; i <sps_num_hor_virtual_boundaries; i++ )     sps_virtual_boundaries_pos_y[i ] u(13)   }  }  if( sps_ptl_dpb_hrd_params_present_flag ) {  sps_general_hrd_params_present_flag u(1)   if(sps_general_hrd_params_present_flag ) {    general_hrd_parameters( )   if( sps_max_sublayers_minus1 > 0 )    sps_sublayer_cpb_params_present_flag u(1)    firstSubLayer =sps_sublayer_cpb_    params_present_flag ? 0 :    sps_max_sublayers_minus1    ols_hrd_parameters( firstSubLayer,   sps_max_sublayers_minus1 )   }  }  field_seq_flag u(1) vui_parameters_present_flag u(1)  if( vui_parameters_present_flag )  vui_parameters( ) /* Specified in /   ITU-TH.SEI | ISO/IEC 23002-7 * sps_extension_flag u(1)  if( sps_extension_flag )   while(more_rbsp_data( ) )    sps_extension_data_flag u(1)  rbsp_trailing_bits() }

Table 2 shows exemplary picture parameter set (PPS) syntax elements insome related examples such as VVC. Both syntax elements related to intracoding and inter coding are included in Table 2. It is noted that for anintra profile which only includes intra slices, inter coding syntaxelements may be present in the PPS but are not used in a decodingprocess of the intra profile. The situation also applies to any stillpicture profile. That is, for a still picture profile which onlyincludes intra slice(s), inter coding syntax elements are not used in adecoding process of the still profile.

TABLE 2 Picture parameter RBSP syntax pic_parameter_set_rbsp( ) {Descriptor  pps_pic_parameter_set_id ue(v)  pps_seq_parameter_set_idu(4)  mixed_nalu_types_in_pic_flag u(1)  pic_width_in_luma_samples ue(v) pic_height_in_luma_samples ue(v)  pps_conformance_window_flag u(1)  if(pps_conformance_window_flag ) {   pps_conf_win_left_offset ue(v)  pps_conf_win_right_offset ue(v)   pps_conf_win_top_offset ue(v)  pps_conf_win_bottom_offset ue(v)  } scaling_window_explicit_signalling_flag u(1)  if(scaling_window_explicit_signalling_flag ) {   scaling_win_left_offsetue(v)   scaling_win_right_offset ue(v)   scaling_win_top_offset ue(v)  scaling_win_bottom_offset ue(v)  }  output_flag_present_flag u(1) subpic_id_mapping_in_pps_flag u(1)  if( subpic_id_mapping_in_pps_flag ){   pps_num_subpics_minus1 ue(v)   pps_subpic_id_len_minus1 ue(v)   for(i = 0; i <= pps_num_subpic_minus1; i++ )    pps_subpic_id[ i ] u(v)  } no_pic_partition_flag u(1)  if( !no_pic_partition_flag ) {  pps_log2_ctu_size_minus5 u(2)   num_exp_tile_columns_minus1 ue(v)  num_exp_tile_rows_minus1 ue(v)   for( i = 0; i <=num_exp_tile_columns_minus1; i++ )    tile_column_width_minus1[ i ]ue(v)   for( i = 0; i <= num_exp_tile_rows_minus1; i++ )   tile_row_height_minus1[ i ] ue(v)   if( NumTilesInPic > 1 )   rect_slice_flag u(1)   if( rect_slice_flag )   single_slice_per_subpic_flag u(1)   if( rect_slice_flag &&!single_slice_per_subpic_flag ) {    num_slices_in_pic_minus1 ue(v)    if( num_slices_in_pic_minus1 > 0 )     tile_idx_delta_present_flagu(1)     for( i = 0; i < num_slices_in_pic_minus1; i++ ) {    if(NumTileColumns > 1 )     slice_width_in_tiles_minus1[ i ] ue(v)    if(NumTileRows > 1 && ( tile_idx_    delta_present_flag ||     SliceTopLeftTileIdx[ i ] %      NumTileColumns = = 0 ) )    slice_height_in_tiles_minus1[ i ] ue(v)    if(slice_width_in_tiles_minus1[ i ] = = 0 &&     slice_height_in_tiles_minus1[ i ] = = 0 &&     RowHeight[SliceTopLeftTileIdx[ i ] /      NumTileColumns ] > 1 ) {    num_exp_slices_in_tile[ i ] ue(v)     for( j = 0; j <num_exp_slices_in_tile[ i ]; j++ )      exp_slice_height_in_ctus_minus1[i ][ j ] ue(v)     i += NumSlicesInTile[ i ] − 1    }    if(tile_idx_delta_present_flag && i <    mun_slices_in_pic_minus1 )    tile_idx_delta[ i ] se(v)    }   }  loop_filter_across_tiles_enabled_flag u(1)  loop_filter_across_slices_enabled_flag u(1)  } cabac_init_present_flag u(1)  for( i = 0; i < 2; i++ )   num_refidx_default_active_minus1[ i ] ue(v)  rpl1_idx_present_flag u(1) init_qp_minus26 se(v)  cu_qp_delta_enabled_flag u(1) pps_chroma_tool_offsets_present_flag u(1)  if(pps_chroma_tool_offsets_present_flag ) {   pps_cb_qp_offset se(v)  pps_cr_qp_offset se(v)   pps_joint_cbcr_qp_offset_present_flag u(1)  if( pps_joint_cbcr_qp_offset_present_flag )    ppsjoint_cbcr_qp_offset_value se(v)  pps_slice_chroma_qp_offsets_present_flag u(1)  pps_cu_chroma_qp_offset_list_enabled_flag u(1)  }  if(pps_cu_chroma_qp_offset_list_enabled_flag ) {  chroma_qp_offset_list_len_minus1 ue(v)   for( i = 0; i <=chroma_qp_offset_list_   len_minus1; i++ ) {    cb_qp_offset_list[ i ]se(v)    cr_qp_offset_list[ i ] se(v)    if(pps_joint_cbcr_qp_offset_present_flag )    joint_cbcr_qp_offset_list[ i] se(v)   }  }  pps_weighted_pred_flag u(1)  pps_weighted_bipred_flagu(1)  deblocking_filter_control_present_flag u(1)  if(deblocking_filter_control_present_flag ) {  deblocking_filter_override_enabled_flag u(1)  pps_deblocking_filter_disabled_flag u(1)   if(!pps_deblocking_filter_disabled_flag ) {    pps_beta_offset_div2 se(v)   pps_tc_offset_div2 se(v)    pps_cb_beta_offset_div2 se(v)   pps_cb_tc_offset_div2 se(v)    pps_cr_beta_offset_div2 se(v)   pps_cr_tc_offset_div2 se(v)   }  }  rpl_info_in_ph_flag u(1)  if(deblocking_filter_override_enabled_flag )   dbf_info_in_ph_flag u(1) sao_info_in_ph_flag u(1)  alf_info_in_ph_flag u(1)  if( (pps_weighted_pred_flag || pps_weighted_bipred_flag )  &&rpl_info_in_ph_flag )   wp_info_in_ph_flag u(1) qp_delta_info_in_ph_flag u(1)  pps_ref_wraparound_enabled_flag u(1) if( pps_ref_wraparound_enabled_flag )   pps_ref_wraparound_offset ue(v) picture_header_extension_present_flag u(1) slice_header_extension_present_flag u(1)  pps_extension_flag u(1)  if(pps_extension_flag )   while( more_rbsp_data( ) )   pps_extension_data_flag u(1)  rbsp_trailing_bits( ) }

Table 3 and Table 4 show exemplary picture header (PH) syntax elementsin some related examples such as VVC. A picture may include acombination of intra and inter slices. When a picture includes onlyintra slices, inter coding syntax elements may be present in the PH butare not used in a decoding process of the picture. To reduce overhead ina picture, in some examples, ph_inter_slice_allowed_flag andph_intra_slice_allowed_flag in Table 4 are used to conditionally signalintra coding related syntax elements and inter coding related syntaxelements.

TABLE 3 Picture header RBSP syntax picture_header_rbsp( ) { Descriptor picture_header_structure( )  rbsp_trailing_bits( ) }

TABLE 4 Picture header structure picture_header_structure( ) {Descriptor  gdr_or_irap_pic_flag u(1)  if( gdr_or_irap_pic_flag )  gdr_pic_flag u(1)  ph_inter_slice_allowed_flag u(1)  if(ph_inter_slice_allowed_flag )   ph_intra_slice_allowed_flag u(1) non_reference_picture_flag u(1)  ph_pic_parameter_set_id ue(v) ph_pic_order_cnt_lsb u(v)  if( gdr_or_irap_pic_flag )  no_output_of_prior_pics_flag u(1)  if( gdr_pic_flag )  recovery_poc_cnt ue(v)  for( i = 0; i < NumExtraPhBits; i++ )  ph_extra_bit[ i ] u(1)  if( sps_poc_msb_flag ) {  ph_poc_msb_present_flag u(1)   if( ph_poc_msb_present_flag )   poc_msb_val u(v)  }  if( sps_alf_enabled_flag && alf_info_in_ph_flag) {   ph_alf_enabled_flag u(1)   if( ph_alf_enabled_flag ) {   ph_num_alf_aps_ids_luma u(3)    for( i = 0; i <ph_num_alf_aps_ids_luma; i++ )     ph_alf_aps_id_luma[ i ] u(3)    if(ChromaArrayType != 0 )     ph_alf_chroma_idc u(2)    if(ph_alf_chroma_idc > 0 )     ph_alf_aps_id_chroma u(3)    if(sps_ccalf_enabled_flag ) {     ph_cc_alf_cb_enabled_flag u(1)     if(ph_cc_alf_cb_enabled_flag )      ph_cc_alf_cb_aps_id u(3)    ph_cc_alf_cr_enabled_flag u(1)     if( ph_cc_alf_cr_enabled_flag )     ph_cc_alf_cr_aps_id u(3)    }   }  }  if( sps_lmcs_enabled_flag ) {  ph_lmcs_enabled_flag u(1)   if( ph_lmcs_enabled_flag ) {   ph_lmcs_aps_id u(2)    if( ChromaArrayType != 0 )    ph_chroma_residual_scale_flag u(1)   }  }  if(sps_explicit_scaling_list_enabled_flag ) {  ph_explicit_scaling_list_enabled_flag u(1)   if(ph_explicit_scaling_list_enabled_flag )    ph_scaling_list_aps_id u(3) }  if( sps_virtual_boundaries_enabled_flag && !sps_virtual_boundaries_present_flag ) {  ph_virtual_boundaries_present_flag u(1)   if(ph_virtual_boundaries_present_flag ) {    ph_num_ver_virtual_boundariesu(2)    for( i = 0; i < ph_num_ver_virtual_boundaries; i++ )    ph_virtual_boundaries_pos_x[ i ] u(13)   ph_num_hor_virtual_boundaries u(2)    for( i = 0; i <ph_num_hor_virtual_boundaries; i++ )     ph_virtual_boundaries_pos_y[ i] u(13)   }  }  if( output_flag_present_flag )   pic_output_flag u(1) if( rpl_info_in_ph_flag )   ref_pic_lists( )  if(partition_constraints_override_enabled_flag )  partition_constraints_override_flag u(1)  if(ph_intra_slice_allowed_flag ) {   if(partition_constraints_override_flag ) {   ph_log2_diff_min_qt_min_cb_intra_slice_luma ue(v)   ph_max_mtt_hierarchy_depth_intra_slice_luma ue(v)    if(ph_max_mtt_hierarchy_depth_intra_    slice_luma != 0 ) {    ph_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)    ph_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)    }    if(qtbtt_dual_tree_intra_flag ) {    ph_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)    ph_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)     if(ph_max_mtt_hierarchy_depth_intra_     slice_chroma != 0 ) {     ph_log2_diff_max_bt_min_qt_intra_ ue(v)      slice_chroma     ph_log2_diff_max_tt_min_qt_intra_ ue(v)      slice_chroma     }   }   }   if( cu_qp_delta_enabled_flag )   ph_cu_qp_delta_subdiv_intra_slice ue(v)   if(pps_cu_chroma_qp_offset_list_enabled_flag )   ph_cu_chroma_qp_offset_subdiv_intra_slice ue(v)  }  if(ph_inter_slice_allowed_flag ) {   if(partition_constraints_override_flag ) {   ph_log2_diff_min_qt_min_cb_inter_slice ue(v)   ph_max_mtt_hierarchy_depth_inter_slice ue(v)    if(ph_max_mtt_hierarchy_depth_inter slice != 0 ) {    ph_log2_diff_max_bt_min_qt_inter_slice ue(v)    ph_log2_diff_max_tt_min_qt_inter_slice ue(v)    }   }   if(cu_qp_delta_enabled_flag )    ph_cu_qp_delta_subdiv_inter_slice ue(v)  if( pps_cu_chroma_qp_offset_list_enabled_flag )   ph_cu_chroma_qp_offset_subdiv_inter_slice ue(v)   if(sps_temporal_mvp_enabled_flag ) {    ph_temporal_mvp_enabled_flag u(1)   if( ph_temporal_mvp_enabled_flag &&    rpl_info_in_ph_flag ) {    ph_collocated_from_10_flag u(1)     if( ( ph_collocated_from_10_flag&&       num_ref_entries[ 0 ][ RplsIdx[ 0 ] ] > 1 ) ||       (!ph_collocated_from_10_flag &&       num_ref_entries[ 1 ][RplsIdx[ 1 ]] > 1 ) )      ph_collocated_ref_idx ue(v)    }   }   mvd_l1_zero_flagu(1)   if( sps_fpel_mmvd_enabled_flag )    ph_fpel_mmvd_enabled_flagu(1)   if( sps_bdof_pic_present_flag )    ph_disable_bdof_flag u(1)  if( sps_dmvr_pic_present_flag )    ph_disable_dmvr_flag u(1)   if(sps_prof_pic_present_flag )    ph_disable_prof_flag u(1)   if( (pps_weighted_pred_flag ||   pps_weighted_bipred_flag )   &&wp_info_in_ph_flag )    pred_weight_table( )  }  if(qp_delta_info_in_ph_flag )   ph_qp_delta se(v)  if(sps_joint_cbcr_enabled_flag )   ph_joint_cbcr_sign_flag u(1)  if(sps_sao_enabled_flag && sao_info_in_ph_flag ) {  ph_sao_luma_enabled_flag u(1)   if( ChromaArrayType != 0 )   ph_sao_chroma_enabled_flag u(1)  }  if( sps_dep_quant_enabled_flag )  ph_dep_quant_enabled_flag u(1)  if( sps_sign_data_hiding_enabled_flag&&  !ph_dep_quant_enabled_flag )   pic_sign_data_hiding_enabled_flagu(1)  if( deblocking_filter_override_enabled_flag  &&dbf_info_in_ph_flag ) {   ph_deblocking_filter_override_flag u(1)   if(ph_deblocking_filter_override_flag ) {   ph_deblocking_filter_disabled_flag u(1)    if(!ph_deblocking_filter_disabled_flag ) {     ph_beta_offset_div2 se(v)    ph_tc_offset_div2 se(v)     ph_cb_beta_offset_div2 se(v)    ph_cb_tc_offset_div2 se(v)     ph_cr_beta_offset_div2 se(v)    ph_cr_tc_offset_div2 se(v)    }   }  }  if(picture_header_extension_present_flag ) {   ph_extension_length ue(v)  for( i = 0; i < ph_extension_length; i++)    ph_extension_data_byte[ i] u(8)  } }

III. Exemplary Profile Information

Table 5 shows exemplary profile information in some related examplessuch as VVC. The profile information may present in profile_tier_level () in SPS and include general constraint informationgeneral_constraint_info( ), as shown in Table 5.

Table 6 shows exemplary general constraint information in some relatedexamples such as VVC. A first flag such as an intra only constraint flag(e.g., infra_only_constraint_flag in Table 6) in the general constraintinformation can be used to indicate whether a slice type of an imageslice conforming to a profile is intra slice. The first flag equal to 1specifies that the slice type of the image slice conforming to theprofile is intra slice (slice_type=I slice). The first flag equal to 0does not impose such a constraint.

TABLE 5 Profile information in SPS profile_tier_level(profileTierPresentFlag, maxMunSubLayersMinus1 ) { Descriptor  if(profileTierPresentFlag ) {   general_profile_idc u(7)  general_tier_flag u(1)   general_constraint_info( )  } general_level_idc u(8)  ... }

TABLE 6 General constraint information in profile informationgeneral_constraint_info( ) { Descriptor  general_progressive_source_flagu(1)  general_interlaced_source_flag u(1) general_non_packed_constraint_flag u(1) general_frame_only_constraint_flag u(1) general_non_projected_constraint_flag u(1)  intra_only_constraint_flagu(1)  ... }

Bitstreams conforming to a Main 10 profile may obey the followingconstraints: (i) referenced SPSs have chroma_format_idc equal to 0 or 1;(ii) referenced SPSs have bit_depth_minus8 in the range of 0 to 2,inclusive; (iii) referenced SPSs have sps_palette_enabled_flag equal to0; (iv) general_level_idc and sublayer_level_idc[i] for all values of iin a view parameter set (VPS) (when available) and in the referencedSPSs are not be equal to 255 (which indicates level 8.5); and (v) thetier and level constraints specified for the Main 10 profile in VVC, asapplicable, can be fulfilled.

Conformance of a bitstream to the Main 10 profile is indicated bygeneral_profile_idc being equal to 1. A decoder conforming to the Main10 profile at a specific level of a specific tier is capable of decodingall bitstreams for which all of the following conditions apply: (i) thebitstream is indicated to conform to the Main 10 profile; (ii) thebitstream is indicated to conform to a tier that is lower than or equalto the specified tier; and (iii) the bitstream is indicated to conformto a level that is not level 8.5 and is lower than or equal to thespecified level.

Bitstreams conforming to a Main 4:4:4 10 profile may obey the followingconstraints: (i) referenced SPSs have chroma_format_idc in the range of0 to 3, inclusive; (ii) referenced SPSs have bit_depth_minus8 in therange of 0 to 2, inclusive; (iii) general_level_idc andsublayer_level_idc[i] for all values of i in a VPS (when available) andin the referenced SPSs are be equal to 255 (which indicates level 8.5);and (iv) the tier and level constraints specified for the Main 4:4:4 10profile in VVC, as applicable, can be fulfilled.

Conformance of a bitstream to the Main 4:4:4 10 profile is indicated bygeneral_profile_idc being equal to 2. A decoder conforming to the Main4:4:4 10 profile at a specific level of a specific tier is capable ofdecoding all bitstreams for which all of the following conditions apply:(i) the bitstream is indicated to conform to the Main 4:4:4 10 or Main10 profile; (ii) the bitstream is indicated to conform to a tier that islower than or equal to the specified tier; and (iii) the bitstream isindicated to conform to a level that is not level 8.5 and is lower thanor equal to the specified level.

IV. Profile Information for Video Sequence Including Only Intra Slices

In some related examples, an SPS-level flag (e.g.,sps_inter_allowed_flag) can be used to indicate that only intra slicesare included in a coded video sequence or bitstream. The flag can beused to skip signaling of inter coding related syntax elements to reduceredundancy. For example, when sps_inter_allowed_flag equals to 1, intercoding related syntax elements can exist in the SPS. Whensps_inter_allowed_flag equals to 0, only intra coding related syntaxelements can exist in the SPS.

Additionally, in some related examples, a PPS-level flag (e.g.,pps_inter_allowed_flag) can be used to indicate that only intra slicesare included in a coded video sequence. The flag can be used to skipsignaling of inter coding related syntax elements to reduce redundancy.For example, when pps_inter_allowed_flag equals to 1, inter codingrelated syntax elements can exist in the PPS. Whenpps_inter_allowed_flag equals to 0, only intra coding related syntaxelements can exist in the PPS.

This disclosure includes methods for using profile information toindicate when only intra slices are included in a coded video sequence.

According to aspects of the disclosure, an all intra profile can be usedto indicate that only intra slices are included in the coded videosequence. In the all intra profile, all slices conforming to thisprofile are intra coded. The all intra profile can be indicated byprofile information such as profile identification information (e.g.,general_profile_idc in Table 5).

A still picture profile can be used to indicate that only intra slicesare included in the coded video sequence. In the still picture profile,all slices conforming to this profile are intra coded. The still picturecan be indicated by profile information such as profile identificationinformation (e.g., general profile idc). The still picture profile canbe used for still photography captured by cameras, computer generatedimages, extraction of snapshots from video sequences, and the like. Thestill picture profile can have a subset of the capabilities of the Main10 profile described above.

In an embodiment, for a still picture profile, a second flag such as aone picture only constraint flag (e.g., one_picture_only_constraint_flagin Table 7) can be included in profile information. The one picture onlyconstraint flag can indicate whether all slices are intra coded andthere is only one picture in the coded video sequence. In an example,the one picture only constraint flag equal to 1 specifies that allslices conforming to the still picture profile in the coded videosequence are intra coded (e.g., slice_type=I slice) and there is onlyone picture in the coded video sequence. The one picture only constraintflag equal to 0 does not impose such a constraint.

In an embodiment, the one picture only constraint flag is signaled ingeneral constraint information (e.g., general_constraint_info( )) inprofile information (e.g., profile_tier_level 0). Table 7 provides anexample of the general constraint information including the one pictureonly constraint flag. As described above, the general constraintinformation in Table 7 can be included in profile information such asprofile_tier_level( ) in Table 5.

TABLE 7 General constraint information including one picture onlyconstraint flag General_constraint_info( ) { Descriptor general_progressive_source_flag u(1)  general_interlaced_source_flagu(1)  general_non_packed_constraint_flag u(1) general_frame_only_constraint_flag u(1) general_non_projected_constraint_flag u(1) one_picture_only_constraint_flag u(1)  intra_only_constraint_flag u(1) ... }

According to aspects of the disclosure, one or more constraints can beapplied between the first and second flags, such as the intra onlyconstraint flag and the one picture only constraint flag in thebitstream conformance.

In an embodiment, as shown in Table 7, the one picture only constraintflag is signaled before the intra only constraint flag. When the onepicture only constraint flag indicates that all slices conforming to thestill picture profile in the coded video sequence are intra coded andincluded in one picture (e.g., one_picture_only_constraint_flag=1 inTable 7), the intra only constraint flag can be set to indicate that aslice type of a slice conforming to the still picture profile is intraslice (e.g., infra_only_constraint_flag=1 in Table 7) based on thebitstream conformance.

In an embodiment, the one picture only constraint flag equal to 1specifies that a slice type of a slice conforming to the still pictureprofile is intra slice (e.g., slice_type=I slice) and there is only onepicture in the bitstream. The one picture only constraint flag equal to0 does not impose such a constraint. The intra only constraint flagequal to 1 specifies that a slice type of a slice is intra slice(slice_type=I slice). The intra only constraint flag equal to 0 does notimpose such a constraint. Based on the bitstream conformance, when theone picture only constraint flag is true, the intra only constraint flagis also true.

In an embodiment, when the one picture only constraint flag is equal to1, the only one picture in the coded video sequence can be an intrarandom access picture (IRAP), such as an instantaneous decoding refresh(IDR) picture or a clean random access (CRA) picture.

In an embodiment, when the one picture only constraint flag is equal to1, video parameter set (VPS) may not present and a number of layers ofthe coded video sequence may be equal to 1.

In an embodiment, when the one picture only constraint flag is equal to1, a reference picture list (RPL) and a picture order count (POC) maynot present in the picture header or slice header.

In an embodiment, when the one picture only constraint flag is equal to1, an access unit delimiter (AUD) and an end of stream (EOS) networkabstraction layer (NAL) units may not be present in the bitstream.

In an embodiment, for an all intra profile, the intra only constraintflag indicates that all the slices conforming to this profile are onlyintra coded, for example when the intra only constraint flag is setto 1. Therefore, in the all intra profile, only intra slices can existin the bitstream.

In an embodiment, for a still picture profile, both of the one pictureonly constraint flag and the intra only constraint flag can be set as 1,indicating only intra slices can exist in the bitstream and only onepicture can exist in the bitstream.

In an embodiment, for a still picture profile, the one picture onlyconstraint flag can be set as 1, indicating only intra slices can existin the bitstream and only one picture can exist in the bitstream.

According to aspects of the disclosure, one or more non-intra relatedsyntax elements may be excluded based on the intra only constraint flag.For example, when the intra only constraint flag is present andindicates that all slices in the bitstream are intra coded, for examplewhen the intra only constraint flag equals to 1, non-intra relatedsyntax elements are not signaled.

In an embodiment, when the intra only constraint flag is present andindicates that all slices in the bitstream are intra coded, for examplewhen the intra only constraint flag equals to 1, one or more flags maybe set to 0. For example, both sps_inter_allowed_flag andpps_inter_allowed_flag described above can be set as 0. When the intraonly constraint flag is not present or equals to 0, such a constraintdoes not apply to the one or more flags, such as sps_inter_allowed_flagand pps_inter_allowed_flag.

According to aspects of the disclosure, one or more non-intra relatedsyntax elements may be excluded based on the one picture only constraintflag. For example, when the one picture only constraint flag is presentand indicates that all slices in the bitstream are intra coded and onlyone picture exists in the bitstream, for example when the one pictureonly constraint flag equals to 1, non-intra related syntax elements arenot signaled.

In an embodiment, when the one picture only constraint flag is presentand indicates that all slices in the bitstream are intra coded and onlyone picture exists in the bitstream, for example when the one pictureonly constraint flag equals to 1, one or more flag may be set to 0. Forexample, both sps_inter_allowed_flag and pps_inter_allowed_flagdescribed above can be set as 0. When the one picture only constraintflag is not present or equals to 0, such a constraint does not apply tothe one or more flags, such a sps_inter_allowed_flag andpps_inter_allowed_flag.

According to aspects of the disclosure, a third flag can be used toindicate that all slices in the coded video sequence are intra coded andincluded in one picture. The third flag can be an SPS only one picturepresent flag and signaled separately from the profile information. Forexample, the SPS only one picture present flag can be signaled in SPS.The SPS only one picture present flag equal to 1 specifies that a slicetype of a slice in the coded video sequence is intra slice (slice_type=Islice) and there is only one picture in the sequence. The SPS only onepicture present flag equal to 0 does not impose such a constraint.

In an embodiment, one or more syntax elements may be excluded based onthe one picture only constraint flag. For example, when the one pictureonly constraint flag is present and indicates that all slices in thebitstream are intra coded and only one picture exists in the bitstream,for example when the one picture only constraint flag equals to 1,non-intra related syntax elements and/or syntax elements regarding POCvalue and RPL are not signaled.

In an embodiment, when the one picture only constraint flag is presentand equals to 1, the SPS only one picture present flag can be set as thesame value as the one picture only constraint flag based on thebitstream conformance.

Table 8 shows some exemplary syntax elements in the general constraintinformation including both the one picture constraint flag and the intraonly constraint flag. As described above, the general constraintinformation in Table 8 can be included in profile information such asprofile_tier_level( ) in Table 5. In Table 8, the one picture constraintflag is general_one_picture_only_constraint_flag.general_one_picture_only_constraint_flag equal to 1 specifies that thereis only one coded picture in the bitstream, andgeneral_one_picture_only_constraint_flag equal to 0 does not impose sucha constraint. In addition, the intra only constraint flag isintra_only_constraint_flag. intra_only_constraint_flag equal to 1specifies that slice type in the slice header is intra slice(sh_slice_type=I), and infra_only_constraint_flag equal to 0 does notimpose such a constraint. When general_one_picture_only_constraint_flagis equal to 1, the value of intra_only_constraint_flag can be set as 1.

TABLE 8 General constraint information syntax general_constraint_info( ){ Descriptor  general_non_packed_constraint_flag u(1) general_frame_only_constraint_flag u(1) general_non_projected_constraint_flag u(1) general_one_picture_only_constraint_flag u(1) intra_only_constraint_flag u(1)  max_bitdepth_constraint_idc u(4) max_chroma_format_constraint_idc u(2)  single_layer_constraint_flagu(1)  all_layers_independent_constraint_flag u(1) no_ref_pic_resampling_constraint_flag u(1) no_res_change_in_clvs_constraint_flag u(1) one_tile_per_pic_constraint_flag u(1) pic_header_in_slice_header_constraint_flag u(1) one_slice_per_pic_constraint_flag u(1) one_subpic_per_pic_constraint_flag u(1) no_qtbtt_dual_tree_intra_constraint_flag u(1) no_partition_constraints_override_constraint_flag u(1) no_sao_constraint_flag u(1)  no_alf_constraint_flag u(1) no_ccalf_constraint_flag u(1)  no_joint_cbcr_constraint_flag u(1) no_mrl_constraint_flag u(1)  no_isp_constraint_flag u(1) no_mip_constraint_flag u(1)  no_ref_wraparound_constraint_flag u(1) no_temporal_mvp_constraint_flag u(1)  no_sbtmvp_constraint_flag u(1) no_amvr_constraint_flag u(1)  no_bdof_constraint_flag u(1) no_dmvr_constraint_flag u(1)  no_cclm_constraint_flag u(1) no_mts_constraint_flag u(1)  no_sbt_constraint_flag u(1) no_lfnst_constraint_flag u(1)  no_affine_motion_constraint_flag u(1) no_mmvd_constraint_flag u(1)  no_smvd_constraint_flag u(1) no_prof_constraint_flag u(1)  no_bcw_constraint_flag u(1) no_ibc_constraint_flag u(1)  no_ciip_constraint_flag u(1) no_gpm_constraint_flag u(1)  no_ladf_constraint_flag u(1) no_transform_skip_constraint_flag u(1)  no_bdpcm_constraint_flag u(1) no_palette_constraint_flag u(1)  no_act_constraint_flag u(1) no_lmcs_constraint_flag u(1)  no_cu_qp_delta_constraint_flag u(1) no_chroma_qp_offset_constraint_flag u(1)  no_dep_quant_constraint_flagu(1)  no_sign_data_hiding_constraint_flag u(1)  no_tsrc_constraint_flagu(1)  no_mixed_nalu_types_in_pic_constraint_flag u(1) no_trail_constraint_flag u(1)  no_stsa_constraint_flag u(1) no_rasl_constraint_flag u(1)  no_radl_constraint_flag u(1) no_idr_constraint_flag u(1)  no_cra_constraint_flag u(1) no_gdr_constraint_flag u(1)  no_aps_constraint_flag u(1)  while(!byte_aligned( ) )   gci_alignment_zero_bit f(1)  gci_num_reserved_bytesu(8)  for( i = 0; i < gci_num_reserved_bytes; i++ )   gci_reserved_byte[i ] u(8) }

According to aspects of the disclosure, bitstreams conforming to theMain 10 or Main 10 Still Picture profile can obey the followingconstraints: (i) in a bitstream conforming to the Main 10 Still Pictureprofile, the bitstream contains only one picture; (ii) referenced SPSshave sps_chroma_format_idc equal to 0 or 1; (iii) referenced SPSs havesps_bit_depth_minus8 in the range of 0 to 2, inclusive; (iv) in abitstream conforming to the Main 10 Still Picture profile, thereferenced SPS have maxdec_pic_buffering_minus1[sps_max_sublayers_minus1] equal to 0; (v)referenced SPSs have sps_palette_enabled_flag equal to 0; (vi) in abitstream conforming to the Main 10 profile that do not conform to theMain 10 Still Picture profile, general_level_idc andsublayer_level_idc[i] for all values of i in the referenced VPS (whenavailable) and in the referenced SPSs are not equal to 255 (whichindicates level 15.5); and (vii) the tier and level constraintsspecified for the Main 10 or Main 10 Still Picture profile in VVC, asapplicable, can be fulfilled.

Conformance of a bitstream to the Main 10 profile can be indicated bythe profile identification information (e.g., general_profile_idc=1 inTable 5).

Conformance of a bitstream to the Main 10 Still Picture profile can beindicated by the one picture constraint flag (e.g.,general_one_picture_only_constraint_flag=1 in Table 8) together with theprofile identification information (e.g., general_profile_idc=1 in Table5).

It is noted that when the conformance of a bitstream to the Main 10Still Picture profile is indicated as specified above, and the indicatedlevel is not level 15.5, the conditions for the indication of theconformance of the bitstream to the Main 10 profile are also fulfilled.

A decoder conforming to the Main 10 profile at a specific level of aspecific tier is capable of decoding all bitstreams for which all of thefollowing conditions apply: (i) the bitstream is indicated to conform tothe Main 10 or Main 10 Still Picture profile; (ii) the bitstream isindicated to conform to a tier that is lower than or equal to thespecified tier; and (iii) the bitstream is indicated to conform to alevel that is not level 15.5 and is lower than or equal to the specifiedlevel.

A decoder conforming to the Main 10 Still Picture profile at a specificlevel of a specific tier is capable of decoding all bitstreams for whichall of the following conditions apply: (i) the bitstream is indicated toconform to the Main 10 Still Picture profile; (ii) the bitstream isindicated to conform to a tier that is lower than or equal to thespecified tier; and (iii) the bitstream is indicated to conform to alevel that is not level 15.5 and is lower than or equal to the specifiedlevel.

According to aspects of the disclosure, bitstreams conforming to theMain 4:4:4 10 or Main 4:4:4 10 Still Picture profile can obey thefollowing constraints: (i) in a bitstream conforming to the Main 4:4:410 Still Picture profile, the bitstream contains only one picture; (ii)referenced SPSs have sps_chroma_format_idc in the range of 0 to 3,inclusive; (iii) referenced SPSs have sps_bit_depth_minus8 in the rangeof 0 to 2, inclusive; (iv) in a bitstream conforming to the Main 4:4:410 Still Picture profile, the referenced SPS have maxdec_pic_buffering_minus1[sps_max_sublayers_minus1] equal to 0; (v) in abitstream conforming to the Main 4:4:4 10 profile that does not conformto the Main 4:4:4 10 Still Picture profile, general_level_idc andsublayer_level_idc[i] for all values of i in the referenced VPS (whenavailable) and in the referenced SPSs are not equal to 255 (whichindicates level 15.5); and (vi) the tier and level constraints specifiedfor the Main 4:4:4 10 or Main 4:4:4 10 Still Picture profile in VVC, asapplicable, can be fulfilled.

Conformance of a bitstream to the Main 4:4:4 10 profile is indicated bythe profile identification information (e.g., general_profile_idc=2 inTable 5).

Conformance of a bitstream to the Main 4:4:4 10 Still Picture profile isindicated by the one picture constraint flag (e.g.,general_one_picture_only_constraint_flag=1 in Table 8) together with theprofile identification information (e.g., general_profile_idc=2 in Table5).

It is noted that when the conformance of a bitstream to the Main 104:4:4 Still Picture profile is indicated as specified above, and theindicated level is not level 15.5, the conditions for the indication ofthe conformance of the bitstream to the Main 10 4:4:4 profile are alsofulfilled.

A decoder conforming to the Main 4:4:4 10 profile at a specific level ofa specific tier is capable of decoding all bitstreams for which all ofthe following conditions apply: (i) the bitstream is indicated toconform to the Main 4:4:4 10, Main 10, Main 4:4:4 10 Still Picture, orMain 10 Still Picture profile; (ii) the bitstream is indicated toconform to a tier that is lower than or equal to the specified tier; and(iii) the bitstream is indicated to conform to a level that is not level15.5 and is lower than or equal to the specified level.

A decoder conforming to the Main 4:4:4 10 Still Picture profile at aspecific level of a specific tier is capable of decoding all bitstreamsfor which all of the following conditions apply: (i) the bitstream isindicated to conform to the Main 4:4:4 10 Still Picture or Main 10 StillPicture profile; (ii) the bitstream is indicated to conform to a tierthat is lower than or equal to the specified tier; and (iii) thebitstream is indicated to conform to a level that is not level 15.5 andis lower than or equal to the specified level.

V. Groups of General Constraint Flags

The general constraint information as described above can include aplurality of syntax elements (e.g., syntax elements in Table 8).However, a decoder may only need to decode a subset of the plurality ofsyntax elements to conform to a profile. This disclosure includesmethods for grouping the plurality of syntax elements in the generalconstraint information. The grouping of the plurality of syntax elementscan allow the decoder to terminate parsing of the general constraintinformation early, which can speed up the decoding process.

According to aspects of the disclosure, the plurality of syntax elementsin the general constraint information can be grouped based on usagescenario such as profiles. A subgroup inside a group can also exist.Each group or subgroup of syntax elements includes a trunk of syntaxelements which are present consecutively in the bitstream. Therefore,the decoder can terminate the parsing of the general constraintinformation early with the knowledge of the groups.

In some embodiments, the decoder can have the knowledge of a totalnumber and an order of the groups of syntax elements included in thegeneral constraint information.

In an embodiment, as shown in Table 9, the general constraintinformation includes three groups of syntax elements:non-intra-non-inter group (Group I), intra group (Group II), and intergroup (Group III). For example, the intra group (Group II) includes atrunk of syntax elements related to intra coding tools, the inter group(Group III) includes a trunk of syntax elements related to inter codingtools, and the non-intra-non-inter group (Group I) includes a trunk ofsyntax elements related to neither of intra coding tools nor intercoding tools. In an example, the non-intra-non-inter group (Group I) ispresent in the bitstream first, then followed by the intra group (GroupII), and the inter group (Group III) appears last.

As described above, the general constraint information in Table 9 can beincluded in profile information such as profile_tier_level( ) in Table5.

TABLE 9 General constraint information including three groups of syntaxelements general_constraint_info( ) { Descriptor //Group I:non-intra-non-inter group  general_non_packed_constraint_flag u(1) general_frame_only_constraint_flag u(1) general_non_projected_constraint_flag u(1) general_one_picture_only_constraint_flag u(1) intra_only_constraint_flag u(1)  max_bitdepth_constraint_idc u(4) max_chroma_format_constraint_idc u(2)  single_layer_constraint_flagu(1)  all_layers_independent_constraint_flag u(1) no_ref_pic_resampling_constraint_flag u(1) no_res_change_in_clvs_constraint_flag u(1) one_tile_per_pic_constraint_flag u(1) pic_header_in_slice_header_constraint_flag u(1) one_slice_per_pic_constraint_flag u(1) one_subpic_per_pic_constraint_flag u(1) no_partition_constraints_override_constraint_flag u(1) no_sao_constraint_flag u(1)  no_alf constraint_flag u(1) no_ccalf_constraint_flag u(1)  no_joint_cbcr_constraint_flag u(1) no_mts_constraint_flag u(1)  no_ladf_constraint_flag u(1) no_transform_skip_constraint_flag u(1)  no_act_constraint_flag u(1) no_lmcs_constraint_flag u(1)  no_cu_qp_delta_constraint_flag u(1) no_chroma_qp_offset_constraint_flag u(1)  no_dep_quant_constraint_flagu(1)  no_sign_data_hiding_constraint_flag u(1)  no_tsrc_constraint_flagu(1)  no_mixed_nalu_types_in_pic_constraint_flag u(1) no_trail_constraint_flag u(1)  no_stsa_constraint_flag u(1) no_rasl_constraint_flag u(1)  no_radl_constraint_flag u(1) no_idr_constraint_flag u(1)  no_cra_constraint_flag u(1) no_gdr_constraint_flag u(1)  no_aps_constraint_flag u(1) //end of GroupI:non-intra-non-inter group //Group II: intra group no_qtbtt_dual_tree_intra_constraint_flag u(1)  no_mrl_constraint_flagu(1)  no_isp_constraint_flag u(1)  no_mip_constraint_flag u(1) no_cclm_constraint_flag u(1)  no_lfnst_constraint_flag u(1) no_ibc_constraint_flag u(1)  no_bdpcm_constraint_flag u(1) no_palette_constraint_flag u(1) //end of Group II:intra group //GroupIII: inter group  no_ref_wraparound_constraint_flag u(1) no_temporal_mvp_constraint_flag u(1)  no_sbtmvp_constraint_flag u(1) no_amvr_constraint_flag u(1)  no_bdof_constraint_flag u(1) no_dmvr_constraint_flag u(1)  no_sbt_constraint_flag u(1) no_affine_motion_constraint_flag u(1)  no_mmvd_constraint_flag u(1) no_smvd_constraint_flag u(1)  no_prof_constraint_flag u(1) no_bcw_constraint_flag u(1)  no_ciip_constraint_flag u(1) no_gpm_constraint_flag u(1) //end of Group III:inter group  while(!byte_aligned( ) )   gci_alignment_zero_bit f(1)  gci_num_reserved_bytesu(8)  for( i = 0; i < gci_num_reserved_bytes; i++ )   gci_reserved_byte[i ] u(8) }

In Main 10 Still Picture or Main 10 4:4:4 Still Picture profile,conformance of a bitstream can be indicated by a onepicture_only_constraint_flag (e.g.,general_one_picture_only_constraint_flag=1 in Table 9) together withprofile identification information (e.g., general_profile_idc=1 in Table5). When the one picture_only_constraint_flag is equal to 1, the valueof an intra only constraint flag is equal to 1. In other profiles, suchas a profile including only intra pictures, theintra_only_constraint_flag can also be equal to 1.

When the intra_only_constraint_flag is equal to 1, the values of thesyntax elements in the inter group (Group III), such asno_ref_wraparound_constraint_flag, no_temporal_mvp_constraint_flag, andthe like in Table 9, are all equal to 1.

Therefore, with the knowledge of the groups of syntax elements, thedecoder is able to terminate the parsing of the general constraintinformation early which can be beneficial to the decoding speed andprocedure.

In an embodiment, as shown in Table 10, the general constraintinformation includes two groups of syntax elements: non-inter group(Group I) and inter group (Group II). The inter group (Group II) caninclude a trunk of syntax elements related to inter coding tools. Thenon-inter group (Group I) can include a trunk of syntax elements notrelated to the inter coding tools. In an example, the non-inter group(Group I) appears in the bitstream first followed by the inter group(Group II).

As described above, the general constraint information in Table 10 canbe included in profile information such as profile_tier_level( ) inTable 5.

TABLE 10 General constraint information including two groups of syntaxelements general_constraint_info( ) ( Descriptor //Group I: non-intergroup  general_non_packed_constraint_flag u(1) general_frame_only_constraint_flag u(1) general_non_projected_constraint_flag u(1) general_one_picture_only_constraint_flag u(1) intra_only_constraint_flag u(1)  max_bitdepth_constraint_idc u(4) max_chroma_format_constraint_idc u(2)  single_layer_constraint_flagu(1)  all_layers_independent_constraint_flag u(1) no_ref_pic_resampling_constraint_flag u(1) no_res_change_in_clvs_constraint_flag u(1) one_tile_per_pic_constraint_flag u(1) pic_header_in_slice_header_constraint_flag u(1) one_slice_per_pic_constraint_flag u(1) one_subpic_per_pic_constraint_flag u(1) no_partition_constraints_override_constraint_flag u(1) no_sao_constraint_flag u(1)  no_alf_constraint_flag u(1) no_ccalf_constraint_flag u(1)  no_joint_cbcr_constraint_flag u(1) no_mts_constraint_flag u(1)  no_ladf_constraint_flag u(1) no_transform_skip_constraint_flag u(1)  no_act_constraint_flag u(1) no_lmcs_constraint_flag u(1)  no_cu_qp_delta_constraint_flag u(1) no_chroma_qp_offset_constraint_flag u(1)  no_dep_quant_constraint_flagu(1)  no_sign_data_hiding_constraint_flag u(1)  no_tsrc_constraint_flagu(1)  no_mixed_nalu_types_in_pic_constraint_flag u(1) no_trail_constraint_flag u(1)  no_stsa_constraint_flag u(1) no_rasl_constraint_flag u(1)  no_radl_constraint_flag u(1) no_idr_constraint_flag u(1)  no_cra_constraint_flag u(1) no_gdr_constraint_flag u(1)  no_aps_constraint_flag u(1) no_qtbtt_dual_tree_intra_constraint_flag u(1)  no_mrl_constraint_flagu(1)  no_jsp_constraint_flag u(1)  no_mip_constraint_flag u(1) no_cclm_constraint_flag u(1)  no_lfnst_constraint_flag u(1) no_ibc_constraint_flag u(1)  no_bdpcm_constraint_flag u(1) no_palette_constraint_flag u(1) //end of Group I:non-inter group//Group II: inter group  no_ref_wraparound_constraint_flag u(1) no_temporal_mvp_constraint_flag u(1)  no_sbtmvp_constraint_flag u(1) no_amvr_constraint_flag u(1)  no_bdof_constraint_flag u(1) no_dmvr_constraint_flag u(1)  no_sbt_constraint_flag u(1) no_affine_motion_constraint_flag u(1)  no_mmvd_constraint_flag u(1) no_smvd_constraint_flag u(1)  no_prof_constraint_flag u(1) no_bcw_constraint_flag u(1)  no_ciip_constraint_flag u(1) no_gpm_constraint_flag u(1) //end of Group II:inter group  while(!byte_aligned( ) )   gci_alignment_zero_bit f(1)  gci_num_reserved_bytesu(8)  for( i = 0; i < gci_num_reserved_bytes; i++ )   gci_reserved_byte[i ] u(8) }

In Main 10 Still Picture or Main 10 4:4:4 Still Picture profile,conformance of a bitstream can be indicated by the onepicture_only_constraint_flag (e.g.general_one_picture_only_constraint_flag=1 in Table 10) together withthe profile identification information (general_profile_idc=1 in Table5). When the one picture only constraint flag is equal to 1, the valueof the intra_only_constraint_flag is equal to 1. In other profiles, suchas a profile including only intra pictures, theintra_only_constraint_flag can also be equal to 1.

When the intra_only_constraint_flag is equal to 1, the values of syntaxelements in the inter group (Group II), such asno_ref_wraparound_constraint_flag, no_temporal_mvp_constraint_flag, andthe like in Table 10, are all equal to 1.

Therefore, with the knowledge of the groups of syntax elements, thedecoder is able to terminate the parsing of the general constraintinformation early which an be beneficial to the decoding speed andprocedure.

According to some embodiments, whenever a new syntax element isintroduced to the general constraint information (e.g.,general_constraint_info ( ) in Table 9 or Table 10), the new syntaxelement can be included in an existing group or subgroup so that thegeneral constraint information does not need to form a new grouprelative to the existing groups.

In an embodiment, for the general constraint information including thenon-intra-non-inter group (Group I), intra group (Group II), and intergroup (Group III), when a new syntax element related to an intra codingtool is to be included in the general constraint information, the newsyntax element can be included in the intra group (Group II). When a newsyntax element related to an inter coding tool is to be included in thegeneral constraint information, the new syntax element can be includedin the inter group (Group III). When a new syntax element is not relatedto an intra coding nor an inter coding tool, the new syntax element canbe included in the non-intra-non-inter group (Group I).

In an example as shown in Table 11, a new syntax element no weightedprediction constraint flag (e.g., no_weighted_pred_constraint_flag)specifying whether weighted prediction can be applied to a P slice isintroduced to the general constraint information including three groupsof syntax elements, the new syntax element can be included in the intergroup (Group III) since it is a syntax element related to an intercoding tool.

As described above, the general constraint information in Table 11 canbe included in profile information such as profile_tier_level( ) inTable 5.

TABLE 11 A new syntax element introducing to the general constraintinformation including three groups of syntax elementsgeneral_constraint_info( ) ( Descriptor //Group I: non-intra-non-intergroup ... //end of Group I:non-intra-non-inter group //Group II: intragroup ... //end of Group II:intra group //Group III: inter group no_ref_wraparound_constraint_flag u(1)  no_temporal_mvp_constraint_flagu(1)  no_sbtmvp_constraint_flag u(1)  no_amvr_constraint_flag u(1) no_bdof_constraint_flag u(1)  no_dmvr_constraint_flag u(1) no_sbt_constraint_flag u(1)  no_affine_motion_constraint_flag u(1) no_mmvd_constraint_flag u(1)  no_smvd_constraint_flag u(1) no_prof_constraint_flag u(1)  no_bcw_constraint_flag u(1) no_ciip_constraint_flag u(1)  no_gpm_constraint_flag u(1) no_weighted_pred_constraint_flag u(1) //end of Group III:inter group while( !byte_aligned( ) )   gci_alignment_zero_bit f(1) gci_num_reserved_bytes u(8)  for( i = 0; i < gci_num_reserved_bytes;i++ )   gci_reserved_byte[ i ] u(8) }

In an embodiment, for the general constraint information including thenon-inter group (Group I) and the inter group (Group II), when a newsyntax element related to an inter coding tool is to be included in thegeneral constraint information, the new syntax can be included in theinter group (Group II). When a new syntax element not related to aninter coding tool is to be included in the general constraintinformation, the new syntax element can be included in the non-intergroup (Group I).

In an example as shown in Table 12, a new syntax element no weightedprediction constraint flag (e.g., no_weighted_pred_constraint_flag)specifying whether weighted prediction can be applied to a P slice isintroduced to the general constraint information including two groups ofsyntax elements, the new syntax element can be included in the intergroup (Group II) since it is a syntax element related to an inter codingtool.

As described above, the general constraint information in Table 12 canbe included in profile information such as profile_tier_level( ) inTable 5.

TABLE 12 A new syntax element introducing to the general constraintinformation including two groups of syntax elementsgeneral_constraint_info( ) ( Descriptor //Group I: other group ... //endof Group I:other group //Group II: inter group no_ref_wraparound_constraint_flag u(1)  no_temporal_mvp_constraint_flagu(1)  no_sbtmvp_constraint_flag u(1)  no_amvr_constraint_flag u(1) no_bdof_constraint_flag u(1)  no_dmvr_constraint_flag u(1) no_sbt_constraint_flag u(1)  no_affine_motion_constraint_flag u(1) no_mmvd_constraint_flag u(1)  no_smvd_constraint_flag u(1) no_prof_constraint_flag u(1)  no_bcw_constraint_flag u(1) no_ciip_constraint_flag u(1)  no_gpm_constraint_flag u(1) no_weighted_pred_constraint_flag u(1) //end of Group II:inter group while( !byte_aligned( ) )   gci_alignment_zero_bit f(1) gci_num_reserved_bytes u(8)  for( i = 0; i < gci_num_reserved_bytes;i++ )   gci_reserved_byte[ i ] u(8) }

According to aspects of the disclosure, byte alignment can be checkedafter each group or subgroup for the ease of parsing and earlytermination.

Table 13 shows an exemplary byte alignment for each group in the generalconstraint information including three groups of syntax elements. Thebyte alignment is checked at the end of each group or subgroup. If thesyntax elements signaled in a group or subgroup are not byte aligned,additional bits can be signaled to ensure the total bits used for eachgroup are byte aligned.

As described above, the general constraint information in Table 13 canbe included in profile information such as profile_tier_level( ) inTable 5.

TABLE 13 Byte alignment for each group in the general constraintinformation including three groups of syntax elementsgeneral_constraint_info( ) ( Descriptor //Group I: non-intra-non-intergroup  general_non_packed_constraint_flag u(1) general_frame_only_constraint_flag u(1) general_non_projected_constraint_flag u(1) general_one_picture_only_constraint_flag u(1) intra_only_constraint_flag u(1)  max_bitdepth_constraint_idc u(4) max_chroma_format_constraint_idc u(2)  single_layer_constraint_flagu(1)  all_layers_independent_constraint_flag u(1) no_ref_pic_resampling_constraint_flag u(1) no_res_change_in_clvs_constraint_flag u(1) one_tile_per_pic_constraint_flag u(1) pic_header_in_slice_header_constraint_flag u(1) one_slice_per_pic_constraint_flag u(1) one_subpic_per_pic_constraint_flag u(1) no_partition_constraints_override_constraint_flag u(1) no_sao_constraint_flag u(1)  no_alf_constraint_flag u(1) no_ccalf_constraint_flag u(1)  no_joint_cbcr_constraint_flag u(1) no_mts_constraint_flag u(1)  no_ladf_constraint_flag u(1) no_transform_skip_constraint_flag u(1)  no_act_constraint_flag u(1) no_lmcs_constraint_flag u(1)  no_cu_qp_delta_constraint_flag u(1) no_chroma_qp_offset_constraint_flag u(1)  no_dep_quant_constraint_flagu(1)  no_sign_data_hiding_constraint_flag u(1)  no_tsrc_constraint_flagu(1)  no_mixed_nalu_types_in_pic_constraint_flag u(1) no_trail_constraint_flag u(1)  no_stsa_constraint_flag u(1) no_rasl_constraint_flag u(1)  no_radl_constraint_flag u(1) no_idr_constraint_flag u(1)  no_cra_constraint_flag u(1) no_gdr_constraint_flag u(1)  no_aps_constraint_flag u(1)  while(!byte_aligned( ) )   gci_alignment_zero_bit f(1) //end of GroupI:non-intra-non-inter group //Group II: intra group no_qtbtt_dual_tree_intra_constraint_flag u(1)  no_mrl_constraint_flagu(1)  no_isp_constraint_flag u(1)  no_mip_constraint_flag u(1) no_cclm_constraint_flag u(1)  no_lfnst_constraint_flag u(1) no_ibc_constraint_flag u(1)  no_bdpcm_constraint_flag u(1) no_palette_constraint_flag u(1)  while( !byte_aligned( ) )  gci_alignment_zero_bit f(1) //end of Group II:intra group //Group III:inter group  no_ref_wraparound_constraint_flag u(1) no_temporal_mvp_constraint_flag u(1)  no_sbtmvp_constraint_flag u(1) no_amvr_constraint_flag u(1)  no_bdof_constraint_flag u(1) no_dmvr_constraint_flag u(1)  no_sbt_constraint_flag u(1) no_affine_motion_constraint_flag u(1)  no_mmvd_constraint_flag u(1) no_smvd_constraint_flag u(1)  no_prof constraint_flag u(1) no_bcw_constraint_flag u(1)  no_ciip_constraint_flag u(1) no_gpm_constraint_flag u(1)  while( !byte_aligned( ) )  gci_alignment_zero_bit f(1) //end of Group III:inter group gci_num_reserved_bytes u(8)  for( i = 0; i < gci_num_reserved_bytes;i++ )   gci_reserved_byte[ i ] u(8) }

Table 14 shows an exemplary byte alignment for each group in the generalconstraint information including two groups of syntax elements. The bytealignment is checked at the end of each group or subgroup. If the syntaxelements signaled in a group or subgroup are not byte aligned,additional bits are signaled to ensure the total bits used for eachgroup are byte aligned.

As described above, the general constraint information in Table 14 canbe included in profile information such as profile_tier_level( ) inTable 5.

TABLE 14 Byte alignment for each group in the general constraintinformation including two groups of syntax elementsgeneral_constraint_info( ) ( Descriptor //Group I: other group general_non_packed_constraint_flag u(1) general_frame_only_constraint_flag u(1) general_non_projected_constraint_flag u(1) general_one_picture_only_constraint_flag u(1) intra_only_constraint_flag u(1)  max_bitdepth_constraint_idc u(4) max_chroma_format_constraint_idc u(2)  single_layer_constraint_flagu(1)  all_layers_independent_constraint_flag u(1) no_ref_pic_resampling_constraint_flag u(1) no_res_change_in_clvs_constraint_flag u(1) one_tile_per_pic_constraint_flag u(1) pic_header_in_slice_header_constraint_flag u(1) one_slice_per_pic_constraint_flag u(1) one_subpic_per_pic_constraint_flag u(1) no_partition_constraints_override_constraint_flag u(1) no_sao_constraint_flag u(1)  no_alf_constraint_flag u(1) no_ccalf_constraint_flag u(1)  no_joint_cbcr_constraint_flag u(1) no_mts_constraint_flag u(1)  no_ladf_constraint_flag u(1) no_transform_skip_constraint_flag u(1)  no_act_constraint_flag u(1) no_lmcs_constraint_flag u(1)  no_cu_qp_delta_constraint_flag u(1) no_chroma_qp_offset_constraint_flag u(1)  no_dep_quant_constraint_flagu(1)  no_sign_data_hiding_constraint_flag u(1)  no_tsrc_constraint_flagu(1)  no_mixed_nalu_types_in_pic_constraint_flag u(1) no_trail_constraint_flag u(1)  no_stsa_constraint_flag u(1) no_rasl_constraint_flag u(1)  no_radl_constraint_flag u(1) no_idr_constraint_flag u(1)  no_cra_constraint_flag u(1) no_gdr_constraint_flag u(1)  no_aps_constraint_flag u(1) no_qtbtt_dual_tree_intra_constraint_flag u(1)  no_mrl_constraint_flagu(1)  no_isp_constraint_flag u(1)  no_mip_constraint_flag u(1) no_cclm_constraint_flag u(1)  no_lfnst_constraint_flag u(1) no_ibc_constraint_flag u(1)  no_bdpcm_constraint_flag u(1) no_palette_constraint_flag u(1)  while( !byte_aligned( ) )  gci_alignment_zero_bit f(1) //end of Group I:non-inter group //GroupII: inter group  no_ref_wraparound_constraint_flag u(1) no_temporal_mvp_constraint_flag u(1)  no_sbtmvp_constraint_flag u(1) no_amvr_constraint_flag u(1)  no_bdof_constraint_flag u(1) no_dmvr_constraint_flag u(1)  no_sbt_constraint_flag u(1) no_affine_motion_constraint_flag u(1)  no_mmvd_constraint_flag u(1) no_smvd_constraint_flag u(1)  no_prof_constraint_flag u(1) no_bcw_constraint_flag u(1)  no_ciip_constraint_flag u(1) no_gpm_constraint_flag u(1)  while( !byte_aligned( ) )  gci_alignment_zero_bit f(1) //end of Group II:inter group gci_num_reserved_bytes u(8)  for( i = 0; i < gci_num_reserved_bytes;i++ )   gci_reserved_byte[ i ] u(8) }

VII. Flowchart

FIG. 8 shows a flow chart outlining an exemplary process (800) accordingto an embodiment of the disclosure. In various embodiments, the process(800) is executed by processing circuitry, such as the processingcircuitry in the terminal devices (210), (220), (230) and (240), theprocessing circuitry that performs functions of the video encoder (303),the processing circuitry that performs functions of the video decoder(310), the processing circuitry that performs functions of the videodecoder (410), the processing circuitry that performs functions of theintra prediction module (452), the processing circuitry that performsfunctions of the video encoder (503), the processing circuitry thatperforms functions of the predictor (535), the processing circuitry thatperforms functions of the intra encoder (622), the processing circuitrythat performs functions of the intra decoder (772), and the like. Insome embodiments, the process (800) is implemented in softwareinstructions, thus when the processing circuitry executes the softwareinstructions, the processing circuitry performs the process (800).

The process (800) may generally start at step (S810), where the process(800) decodes profile information for a plurality of image slices inprediction information of a coded video bitstream. The profileinformation includes profile identification information of a profile inwhich each of the image slices in the coded video bitstream is intracoded. Then, the process (800) proceeds to step (S820).

At step (S820), the process (800) performs intra prediction on each ofthe image slices in the coded video bitstream. Then, the process (800)proceeds to step (S830).

At step (S830), the process (800) reconstructs at least one imagepicture based on the intra prediction. Then, the process (800)terminates.

In an embodiment, the profile information includes a first flagindicating whether each of the image slices in the coded video bitstreamis intra coded and a second flag indicating whether each of the imageslices in the coded video bitstream is included in one picture.

In an embodiment, the first flag is decoded after the second flag andindicates that each of the image slices in the coded video bitstream isintra coded based on the second flag indicating that each of the imageslices in the coded video bitstream is included in one picture.

In an embodiment, the first flag indicates that each of the image slicesin the coded video bitstream is intra coded based on the profileidentification information of the profile in which each of the imagesslice in the coded video bitstream is intra coded.

In an embodiment, the second flag indicates that each of the imageslices in the coded video bitstream is included in one picture based onthe profile being a still picture profile in which only one picture isincluded in the coded video bitstream.

In an embodiment, non-intra related syntax elements are not included inthe prediction information based on one of (i) the first flag indicatingthat each of the image slices in the coded video bitstream is intracoded and (ii) the second flag indicating that each of the image slicesin the coded video bitstream is included in one picture.

In an embodiment, the prediction information includes a third flagindicating whether each of the image slices in the coded video bitstreamis intra coded and included in one picture. The third flag is notincluded in the profile information.

In an embodiment, the third flag indicates that each of the image slicesin the coded video bitstream is intra coded and included in one picturebased on the second flag indicating that each of the image slices in thecoded video bitstream is included in one picture.

FIG. 9 shows another flow chart outlining an exemplary process (900)according to an embodiment of the disclosure. In various embodiments,the process (900) is executed by processing circuitry, such as theprocessing circuitry in the terminal devices (210), (220), (230) and(240), the processing circuitry that performs functions of the videoencoder (303), the processing circuitry that performs functions of thevideo decoder (310), the processing circuitry that performs functions ofthe video decoder (410), the processing circuitry that performsfunctions of the intra prediction module (452), the processing circuitrythat performs functions of the video encoder (503), the processingcircuitry that performs functions of the predictor (535), the processingcircuitry that performs functions of the intra encoder (622), theprocessing circuitry that performs functions of the intra decoder (772),and the like. In some embodiments, the process (900) is implemented insoftware instructions, thus when the processing circuitry executes thesoftware instructions, the processing circuitry performs the process(900).

The process (900) may generally start at step (S910), where the process(900) decodes profile information in prediction information of a codedvideo bitstream. The profile information includes a plurality of groupsof syntax elements and indicates a profile for the coded videobitstream. Then, the process (900) proceeds to step (S920).

At step (S920), the process (900) determines at least one of theplurality of groups of syntax elements based on the profile indicated inthe profile information. Then, the process (900) proceeds to step(S930).

At step (S930), the process (900) decodes syntax elements included inthe prediction information based on the determined at least one of theplurality of groups of syntax elements. Then, the process (900) proceedsto step (S940).

At step (S940), the process (900) reconstructs at least one picturebased on the decoded syntax elements included in the predictioninformation.

In an embodiment, an order of the determined at least one of theplurality of groups of syntax elements for the profile is in accordancewith a predetermined order of the plurality of groups of syntax elementsin the profile information.

In an embodiment, byte alignment is checked for each of the plurality ofgroups of syntax elements in the profile information.

VIII. Computer System

The techniques described above, can be implemented as computer softwareusing computer-readable instructions and physically stored in one ormore computer-readable media. For example, FIG. 10 shows a computersystem (1000) suitable for implementing certain embodiments of thedisclosed subject matter.

The computer software can be coded using any suitable machine code orcomputer language, that may be subject to assembly, compilation,linking, or like mechanisms to create code comprising instructions thatcan be executed directly, or through interpretation, micro-codeexecution, and the like, by one or more computer central processingunits (CPUs), Graphics Processing Units (GPUs), and the like.

The instructions can be executed on various types of computers orcomponents thereof, including, for example, personal computers, tabletcomputers, servers, smartphones, gaming devices, internet of thingsdevices, and the like.

The components shown in FIG. 10 for computer system (1000) are exemplaryin nature and are not intended to suggest any limitation as to the scopeof use or functionality of the computer software implementingembodiments of the present disclosure. Neither should the configurationof components be interpreted as having any dependency or requirementrelating to any one or combination of components illustrated in theexemplary embodiment of a computer system (1000).

Computer system (1000) may include certain human interface inputdevices. Such a human interface input device may be responsive to inputby one or more human users through, for example, tactile input (such as:keystrokes, swipes, data glove movements), audio input (such as: voice,clapping), visual input (such as: gestures), olfactory input (notdepicted). The human interface devices can also be used to capturecertain media not necessarily directly related to conscious input by ahuman, such as audio (such as: speech, music, ambient sound), images(such as: scanned images, photographic images obtain from a still imagecamera), video (such as two-dimensional video, three-dimensional videoincluding stereoscopic video).

Input human interface devices may include one or more of (only one ofeach depicted): keyboard (1001), mouse (1002), trackpad (1003), touchscreen (1010), data-glove (not shown), joystick (1005), microphone(1006), scanner (1007), camera (1008).

Computer system (1000) may also include certain human interface outputdevices. Such human interface output devices may be stimulating thesenses of one or more human users through, for example, tactile output,sound, light, and smell/taste. Such human interface output devices mayinclude tactile output devices (for example tactile feedback by thetouch-screen (1010), data-glove (not shown), or joystick (1005), butthere can also be tactile feedback devices that do not serve as inputdevices), audio output devices (such as: speakers (1009), headphones(not depicted)), visual output devices (such as screens (1010) toinclude CRT screens, LCD screens, plasma screens, OLED screens, eachwith or without touch-screen input capability, each with or withouttactile feedback capability—some of which may be capable to output twodimensional visual output or more than three dimensional output throughmeans such as stereographic output; virtual-reality glasses (notdepicted), holographic displays and smoke tanks (not depicted)), andprinters (not depicted). These visual output devices (such as screens(1010)) can be connected to a system bus (1048) through a graphicsadapter (1050).

Computer system (1000) can also include human accessible storage devicesand their associated media such as optical media including CD/DVD ROM/RW(1020) with CD/DVD or the like media (1021), thumb-drive (1022),removable hard drive or solid state drive (1023), legacy magnetic mediasuch as tape and floppy disc (not depicted), specialized ROM/ASIC/PLDbased devices such as security dongles (not depicted), and the like.

Those skilled in the art should also understand that term “computerreadable media” as used in connection with the presently disclosedsubject matter does not encompass transmission media, carrier waves, orother transitory signals.

Computer system (1000) can also include a network interface (1054) toone or more communication networks (1055). The one or more communicationnetworks (1055) can for example be wireless, wireline, optical. The oneor more communication networks (1055) can further be local, wide-area,metropolitan, vehicular and industrial, real-time, delay-tolerant, andso on. Examples of the one or more communication networks (1055) includelocal area networks such as Ethernet, wireless LANs, cellular networksto include GSM, 3G, 4G, 5G, LTE and the like, TV wireline or wirelesswide area digital networks to include cable TV, satellite TV, andterrestrial broadcast TV, vehicular and industrial to include CANBus,and so forth. Certain networks commonly require external networkinterface adapters that attached to certain general purpose data portsor peripheral buses (1049) (such as, for example USB ports of thecomputer system (1000)); others are commonly integrated into the core ofthe computer system (1000) by attachment to a system bus as describedbelow (for example Ethernet interface into a PC computer system orcellular network interface into a smartphone computer system). Using anyof these networks, computer system (1000) can communicate with otherentities. Such communication can be uni-directional, receive only (forexample, broadcast TV), uni-directional send-only (for example CANbus tocertain CANbus devices), or bi-directional, for example to othercomputer systems using local or wide area digital networks. Certainprotocols and protocol stacks can be used on each of those networks andnetwork interfaces as described above.

Aforementioned human interface devices, human-accessible storagedevices, and network interfaces can be attached to a core (1040) of thecomputer system (1000).

The core (1040) can include one or more Central Processing Units (CPU)(1041), Graphics Processing Units (GPU) (1042), specialized programmableprocessing units in the form of Field Programmable Gate Areas (FPGA)(1043), hardware accelerators for certain tasks (1044), and so forth.These devices, along with Read-only memory (ROM) (1045), Random-accessmemory (1046), internal mass storage (1047) such as internal non-useraccessible hard drives, SSDs, and the like, may be connected through thesystem bus (1048). In some computer systems, the system bus (1048) canbe accessible in the form of one or more physical plugs to enableextensions by additional CPUs, GPU, and the like. The peripheral devicescan be attached either directly to the core's system bus (1048), orthrough a peripheral bus (1049). Architectures for a peripheral businclude PCI, USB, and the like.

CPUs (1041), GPUs (1042), FPGAs (1043), and accelerators (1044) canexecute certain instructions that, in combination, can make up theaforementioned computer code. That computer code can be stored in ROM(1045) or RAM (1046). Transitional data can be also be stored in RAM(1046), whereas permanent data can be stored for example, in theinternal mass storage (1047). Fast storage and retrieve to any of thememory devices can be enabled through the use of cache memory, that canbe closely associated with one or more CPU (1041), GPU (1042), massstorage (1047), ROM (1045), RAM (1046), and the like.

The computer readable media can have computer code thereon forperforming various computer-implemented operations. The media andcomputer code can be those specially designed and constructed for thepurposes of the present disclosure, or they can be of the kind wellknown and available to those having skill in the computer software arts.

As an example and not by way of limitation, the computer system havingarchitecture (1000), and specifically the core (1040) can providefunctionality as a result of processor(s) (including CPUs, GPUs, FPGA,accelerators, and the like) executing software embodied in one or moretangible, computer-readable media. Such computer-readable media can bemedia associated with user-accessible mass storage as introduced above,as well as certain storage of the core (1040) that are of non-transitorynature, such as core-internal mass storage (1047) or ROM (1045). Thesoftware implementing various embodiments of the present disclosure canbe stored in such devices and executed by core (1040). Acomputer-readable medium can include one or more memory devices orchips, according to particular needs. The software can cause the core(1040) and specifically the processors therein (including CPU, GPU,FPGA, and the like) to execute particular processes or particular partsof particular processes described herein, including defining datastructures stored in RAM (1046) and modifying such data structuresaccording to the processes defined by the software. In addition or as analternative, the computer system can provide functionality as a resultof logic hardwired or otherwise embodied in a circuit (for example:accelerator (1044)), which can operate in place of or together withsoftware to execute particular processes or particular parts ofparticular processes described herein. Reference to software canencompass logic, and vice versa, where appropriate. Reference to acomputer-readable media can encompass a circuit (such as an integratedcircuit (IC)) storing software for execution, a circuit embodying logicfor execution, or both, where appropriate. The present disclosureencompasses any suitable combination of hardware and software.

While this disclosure has described several exemplary embodiments, thereare alterations, permutations, and various substitute equivalents, whichfall within the scope of the disclosure. It will thus be appreciatedthat those skilled in the art will be able to devise numerous systemsand methods which, although not explicitly shown or described herein,embody the principles of the disclosure and are thus within the spiritand scope thereof.

APPENDIX A: ACRONYMS AMVP: Advanced Motion Vector Prediction ASIC:Application-Specific Integrated Circuit ATMVP: Alternative/AdvancedTemporal Motion Vector Prediction BMS: Benchmark Set BV: Block VectorCANBus: Controller Area Network Bus CB: Coding Block CD: Compact DiscCPR: Current Picture Referencing CPU: Central Processing Unit CRT:Cathode Ray Tube CTB: Coding Tree Block CTU: Coding Tree Unit CU: CodingUnit DPB: Decoder Picture Buffer DVD: Digital Video Disc FPGA: FieldProgrammable Gate Area GOP: Group of Pictures GPU: Graphics ProcessingUnit

GSM: Global System for Mobile communications

HEVC: High Efficiency Video Coding HRD: Hypothetical Reference DecoderIBC: Intra Block Copy IC: Integrated Circuit JEM: Joint ExplorationModel JVET: Joint Video Exploration Team LAN: Local Area Network LCD:Liquid-Crystal Display LTE: Long-Term Evolution MV: Motion Vector OLED:Organic Light-Emitting Diode PB: Prediction Block PCI: PeripheralComponent Interconnect PH: Picture Header PLD: Programmable Logic DevicePPS: Picture Parameter Setting POC: Picture Order Count PU: PredictionUnit RAM: Random Access Memory RBSP: Raw Byte Sequence Payload ROM:Read-Only Memory RPL: Reference Picture List SCC: Screen Content CodingSDR: Standard Dynamic Range SEI: Supplementary Enhancement InformationSNR: Signal Noise Ratio SPS: Sequence Parameter Set SSD: Solid-stateDrive TU: Transform Unit USB: Universal Serial Bus VUI: Video UsabilityInformation VVC: Versatile Video Coding

What is claimed is:
 1. A method of video decoding in a decoder,comprising: decoding profile information for a plurality of image slicesin prediction information of a coded video bitstream, the profileinformation including profile identification information of a profile inwhich each of the image slices in the coded video bitstream is intracoded; performing intra prediction on each of the image slices in thecoded video bitstream; and reconstructing at least one image picturebased on the intra prediction.
 2. The method of claim 1, wherein theprofile information includes a first flag indicating whether each of theimage slices in the coded video bitstream is intra coded and a secondflag indicating whether each of the image slices in the coded videobitstream is included in one picture.
 3. The method of claim 2, whereinthe first flag is decoded after the second flag and indicates that eachof the image slices in the coded video bitstream is intra coded based onthe second flag indicating that each of the image slices in the codedvideo bitstream is included in one picture.
 4. The method of claim 2,wherein the first flag indicates that each of the image slices in thecoded video bitstream is intra coded based on the profile identificationinformation of the profile in which each of the images slice in thecoded video bitstream is intra coded.
 5. The method of claim 2, whereinthe second flag indicates that each of the image slices in the codedvideo bitstream is included in one picture based on the profile being astill picture profile in which only one picture is included in the codedvideo bitstream.
 6. The method of claim 2, wherein non-intra relatedsyntax elements are not included in the prediction information based onone of (i) the first flag indicating that each of the image slices inthe coded video bitstream is intra coded and (ii) the second flagindicating that each of the image slices in the coded video bitstream isincluded in one picture.
 7. The method of claim 1, wherein theprediction information includes a third flag indicating whether each ofthe image slices in the coded video bitstream is intra coded andincluded in one picture, the third flag not being included in theprofile information.
 8. The method of claim 7, wherein the third flagindicates that each of the image slices in the coded video bitstream isintra coded and included in one picture based on the second flagindicating that each of the image slices in the coded video bitstream isincluded in one picture.
 9. An apparatus, comprising processingcircuitry configured to: decode profile information for a plurality ofimage slices in prediction information of a coded video bitstream, theprofile information including profile identification information of aprofile in which each of the image slices in the coded video bitstreamis intra coded; perform intra prediction on each of the image slices inthe coded video bitstream; and reconstruct at least one image picturebased the intra prediction.
 10. The apparatus of claim 9, wherein theprofile information includes a first flag indicating whether each of theimage slices in the coded video bitstream is intra coded and a secondflag indicating whether each of the image slices in the coded videobitstream is included in one picture.
 11. The apparatus of claim 10,wherein the first flag is decoded after the second flag and indicatesthat each of the image slices in the coded video bitstream is intracoded based on the second flag indicating that each of the image slicesin the coded video bitstream is included in one picture.
 12. Theapparatus of claim 10, wherein the first flag indicates that each of theimage slices in the coded video bitstream is intra coded based on theprofile identification information of the profile in which each of theimages slice in the coded video bitstream is intra coded.
 13. Theapparatus of claim 10, wherein the second flag indicates that each ofthe image slices in the coded video bitstream is included in one picturebased on the profile being a still picture profile in which only onepicture is included in the coded video bitstream.
 14. The apparatus ofclaim 10, wherein non-intra related syntax elements are not included inthe prediction information based on one of (i) the first flag indicatingthat each of the image slices in the coded video bitstream is intracoded and (ii) the second flag indicating that each of the image slicesin the coded video bitstream is included in one picture.
 15. Theapparatus of claim 9, wherein the prediction information includes athird flag indicating whether each of the image slices in the codedvideo bitstream is intra coded and included in one picture, the thirdflag not being included in the profile information.
 16. The apparatus ofclaim 15, wherein the third flag indicates that each of the image slicesin the coded video bitstream is intra coded and included in one picturebased on the second flag indicating that each of the image slices in thecoded video bitstream is included in one picture.
 17. A non-transitorycomputer-readable storage medium storing instructions which whenexecuted by at least one processor cause the at least one processor toperform the method according to claim
 1. 18. A method of video decodingin a decoder, comprising: decoding profile information in predictioninformation of a coded video bitstream, the profile informationincluding a plurality of groups of syntax elements and indicating aprofile for the coded video bitstream; determining at least one of theplurality of groups of syntax elements based on the profile indicated inthe profile information; decoding syntax elements included in theprediction information based on the determined at least one of theplurality of groups of syntax elements; and reconstructing at least onepicture based on the decoded syntax elements included in the predictioninformation.
 19. The method of claim 18, wherein an order of thedetermined at least one of the plurality of groups of syntax elementsfor the profile is in accordance with a predetermined order of theplurality of groups of syntax elements.
 20. The method of claim 18,wherein byte alignment is checked for each of the plurality of groups ofsyntax elements.